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Cat Ba Island is the closest thing Vietnam has to an island holiday for climbing: jungle on top of the limestone cliffs, beaches and jetties down below. But everything here works differently from other crags — climbing on the island is "tolerated rather than permitted": you buy a permit, you pay the landowner, bolt condition changes from sector to sector, and even the question of whether you are allowed to climb has been taken up by the government before.
This guide helps you plan two days on the island: go with the old crag with the old bolts, Butterfly Valley, or put the time into Fisher and Hidden, the two newer sectors maintained by local operators.
What kind of crag
Cat Ba Island is 2.5 to 3.5 hours southeast of Hanoi by road (including the ferry), and it is the southern gateway to Ha Long Bay and Lan Ha Bay. theCrag's area description calls it "mainly limestone sport climbing, 178 routes," with grades from 3a all the way to 9a.
- Five sectors: Butterfly Valley / Liên Minh (71 routes), Squanch Wall / Fisher Valley (44 routes), Hidden Valley / The Farm (38 routes), The Cave / Buddha Cave (17 routes), Ben Beo Harbour (8 routes, closed).
- Style: roofs, slabs, tufa and vertical walls all at once. The Hidden Valley description reads: "From good-gripping routes to slab routes to overhanging roof climbing, the range of styles is wide. A good place to learn lead climbing or multi-pitch". There is also a small bouldering cave.
- Rock and bolts: everything on the island is limestone, but the bolts range from old glue-ins from 2007 to new stainless steel placed in 2026, so each sector has to be judged on its own.
- Who it suits: people who want to fit two or three days of climbing into an island trip. Flying in for climbing alone is not worth it, but it slots neatly in between Hanoi and Lan Ha Bay.
The most important sentence here repeats in the ethics field of every sector page: "Considering that rockfall can happen outdoors at any time, please understand that a helmet is necessary for climbing anywhere on this island." The same paragraph adds: "The Vietnamese government is looking for a reason to close climbing in this area; do not be the reason we lose access to this beautiful area."
When to go
theCrag is direct about the season on Cat Ba: "The winter months are ideal for sport climbing, with cool temperatures (10 to 20 °C) and low rainfall (5 to 25 mm per month)." The downside of winter is the tide, and that is a deep-water bouldering problem, not a problem for the crags on the island.
Hanoi's climate table works as an inland reference (same monsoon system; Cat Ba is an island, so the temperature range is smaller than Hanoi's):
| Month | Average high / low | Rainfall | Rain days | Sunshine hours | Plan |
|---|---|---|---|---|---|
| December | 21.3 / 13.8 °C | 19.5 mm | 5.1 days | 124 hours | Driest and sunniest, and Butterfly Valley is quiet |
| January | 20.2 / 14.1 °C | 19.8 mm | 10.3 days | 74 hours | Just as little rain, but many more rainy days |
| February | 21.7 / 16.4 °C | 20.2 mm | 12.4 days | 45 hours | Sunshine drops noticeably |
| March | 25.9 / 20.5 °C | 35.8 mm | 15.9 days | 47 hours | Rainy season starts |
The rainy season directly changes whether you can walk into the crag. The Butterfly Valley page says: "The valley floods in the rainy season, so some routes cannot be reached, and the alternative approach is to go around the upper rock overhang." The Cave "stays dry apart from the walls sweating when humidity hits 100%", but the approach is a 5-minute steep climb, and after rain they "recommend wearing solid shoes".
Sorting out sun is simpler here than in the main valleys, because there are fewer walls. Fisher Valley is tagged "dry in the rain, sunny in the morning, sheltered", the most comfortable face on the island; Hidden Valley is tagged "almost fully shaded, sheltered, dry in light rain"; Butterfly Valley is tagged "dry in the rain, sunny in the morning, wet in the rain" — two walls in one sector with different notes.
Getting there
Public transport
- Hanoi ⇄ Cat Ba Island bus: 300,000 VND, booked through Cat Ba Climbing, which handles the ferry along with it. The other option is the Ninh Bình ⇄ Cat Ba Island bus, also 300,000 VND, with pickup from the center of Cat Ba town or from hotels on the main road.
- Island bus: to reach The Cave, take route 14 from Cát Hài to the cable car crossing stop, every 30 minutes, 13,000 VND (2026 price), and the drop-off point is right by Ha Sen Road.
- The ferry and the bus are the same ticket. Leave buffer in the plan: the official time from Hanoi, ferry included, is 2.5 to 3.5 hours.
Driving
- Private car from Hanoi or Noi Bai airport ⇄ Cat Ba Island: 2,000,000 VND, door-to-door, ferry included, 2.5 to 3.5 hours.
- Haiphong or Cat Ba airport ⇄ Cat Ba Island has three options: a direct drive plus ferry (1,300,000 VND including the ferry ticket), a split trip (taxi plus ferry plus taxi, 1,000,000 VND excluding the ferry ticket), or a speedboat plus car (price and schedule have to be asked about separately). All three include pickup from your hotel in Cat Ba town.
- On the island you move by motorbike or e-bike. Cat Ba Climbing rents bikes and e-bikes (150,000 VND), and theCrag's description for independent climbers says "all you need is a motorbike or a bicycle". Local taxis are 80,000 VND; a motorbike taxi (xe om) from town to Ben Beo takes 3 minutes for 10,000 VND.
- Hữu Lũng ⇄ Cat Ba Island private car: 2,580,000 VND; there is no direct bus on a fixed schedule.
Parking
| Sector | Where to park | Cost |
|---|---|---|
| Fisher Valley | Ride 12 km north from Cat Ba town (about 25–35 minutes) past Woodstock toward Cat Ba Eco Lodge, with the wall on your right; go around the north end of the reservoir, park at the junction behind it, open the gate on the left, walk the path down to the wall, and close the gate when you leave | Permit 30,000 VND (2026) |
| Hidden Valley | Drive 5 minutes from town or walk 10 minutes to the car park, then about 10 minutes of steep uphill to the wall | Permit 50,000 VND (2026), bought from the landowner at Pizza Hanh Bakery by the gate |
| Butterfly Valley | 10 km from Cat Ba town; for approach details on individual routes, ask Langur's Adventures | Permit from Langur's, plus 30,000 VND to the farm on the south side of the wall |
| The Cave | Park in the alley at number 44 on the north side of Ha Sen Road, pay the homeowner on the way in or out, then 5 minutes of steep uphill | 20,000 VND exit tip (October 2026) |
| Ben Beo | 20 minutes on foot from Cat Ba town, or a 3-minute xe om; look left from the harbour gate, at the cliff beside the brown hotel | Closed |
The parking and approach setup at Fisher Valley is the best of the bunch: since 2022 the approach path has been improved, toilets and showers built, and a few platforms added for resting and looking out. There is WiFi at the wall, and climbing numbers have doubled as a result.
Rules before you go
Permits differ between the four sectors and are not interchangeable. Fisher is 30,000, Hidden 50,000 VND (both 2026 prices), Butterfly needs a permit from Langur's plus 30,000 to the farm, and The Cave is 20,000 paid on the way out. Work out which sectors you are climbing before you decide how the money is carried.
Fisher Valley has the newest bolts on the island. The sector was opened by Asia Outdoors in early 2019 and is now held by Cat Ba Climbing; Typhoon Yagi wrecked the place in 2024, and repairs and improvements have run all the way to 2026, including a new bouldering area and rebuilt viewing platforms. Hidden Valley is also held and maintained by Cat Ba Climbing / Mr. Zoom, which opened new routes there in 2024.
Butterfly Valley is the oldest sector and carries the most warnings. It was developed between 2007 and 2010 by Erik Ferjentsik and Onslo Carrington, and is "the biggest crag on Cat Ba Island". The fixed-point warnings on the page include: "black rusty bolts", "the 7th bolt is loose", "hornet nest at the anchor", "no more fixed points" (listed twice), "rock still falling", "rockfall all the time", "most bolts and the top look very rusty". There is no rebolting note anywhere.
Hidden Valley's warnings: broken anchor bolts, the first hanger has been removed; rusty bolts.
Fisher Valley's warnings: one route needs "14 quickdraws plus fixed points"; loose anchor bolts; a snake behind the first anchor.
Fixed points are not there for top-roping. The ethics field in several sectors says: "Many routes here have horn anchors, permanent carabiners or quickdraws, so use this gear only for lowering and cleaning. If you want to top-rope any route, set up your own anchor system."
The Cave has a Buddha statue and owls. The area description says "there is a shrine in the cave, and protected wildlife (owls)", and the ethics field says "there is a Buddhist meditation area in the cave, please be respectful, and climb only in the designated areas".
Ben Beo has been closed by a government announcement. theCrag is blunt about it: "The government has officially and forcibly closed this crag. Please respect this closure and move on to the other beautiful crags in the area." The same page still lists 8 routes and a 25,000 VND access fee. This is a database-level notice, and the matching government announcement text was not found; in practice, treat it as closed and do not go.
Do not bribe officials. theCrag spells this one out: "Somebody has tried to bribe, and the result is a very bad precedent that will only make things more difficult in the future."
Emergency numbers: police 113, fire 114, ambulance 115; national search and rescue 020 7008 5000 (24 hours, Vietnamese only). The island has medical resources but they are limited in scope, and every Cat Ba Climbing trip includes travel insurance of up to 100,000,000 VND — when you buy your own, check item by item that it covers outdoor climbing, search and rescue, and evacuation.
Routes by level
YDS and V-grade conversions follow the Mountain Project international grade comparison chart and are approximate; "approx." marks grades the sources give without a/b/c (such as 4 or 5+). The original grade is the one that counts.
Beginner: up to 6a (YDS 5.10a and below)
Butterfly Valley and Hidden Valley are the two beginner powerhouses; Fisher Valley's short routes are the cleanest.
| Route | Grade | YDS | Length or pitches | Sector | Notes |
|---|---|---|---|---|---|
| Baby steps | 3 | approx. 5.2 | 2 m | Butterfly Valley | theCrag 2 stars; the easiest route on the island |
| Potato launcher | 4+ | approx. 5.6 | 30 m | Butterfly Valley | theCrag 2 stars |
| Earth Wind & Fire | 4+ | approx. 5.6 | 10 m | The Cave | theCrag 1 star |
| 3d Tufas 101 | 5a | 5.7 | 12 m | The Cave | theCrag 1 star |
| Where the Wild Things Were | 5b | 5.8 | 18 m | The Cave | theCrag 1 star |
| Kiwis first steps | 5c | 5.9 | 13 m | The Cave | theCrag 1 star |
| Chuyen Nui | 5a | 5.7 | 20 m | Butterfly Valley | theCrag 1 star |
| 5 Fun | 5a | 5.7 | 22 m | Butterfly Valley | theCrag 1 star |
| Vu Duyen | 5c | 5.9 | 8 m | Butterfly Valley | theCrag 1 star |
| Bread and Butter | 5c | 5.9 | 23 m | Butterfly Valley | theCrag 1 star |
| Monkey Magic | 5a | 5.7 | 7 m | Hidden Valley | theCrag 2 stars; small bouldering cave |
| No Worries | 4+ | approx. 5.6 | 7 m | Hidden Valley | theCrag 1 star |
| No Problem | 4+ | approx. 5.6 | 7 m | Hidden Valley | theCrag 1 star |
| First Time Get It | 4+ | approx. 5.6 | 7 m | Hidden Valley | theCrag 1 star |
| Tarzan | 5b | 5.8 | 7 m | Hidden Valley | theCrag 1 star |
| Jane | 5c | 5.9 | 7 m | Hidden Valley | theCrag 1 star |
| Pick Pocket | 5b | 5.8 | 11 m | Hidden Valley | theCrag 2 stars |
| Green Lungs | 5c | 5.9 | 13 m | Hidden Valley | theCrag 2 stars |
| Duck on the Lake | 5a | 5.7 | 8 m | Fisher Valley | theCrag 1 star |
| Cosmiclea | 5a | 5.7 | 12 m | Fisher Valley | theCrag 1 star |
| Funky Town | 5b | 5.8 | 20 m | Fisher Valley | theCrag 2 stars |
| Chimney Sweep | 5b | 5.8 | 22 m | Fisher Valley | theCrag 2 stars |
| White Boy Shuffle | 5b | 5.8 | 20 m | Fisher Valley | theCrag 2 stars |
| Long Black | 5b | 5.8 | 18 m | Fisher Valley | theCrag 2 stars |
| Walmart Cookies | 5b | 5.8 | 9 m | Fisher Valley | theCrag 2 stars |
| Funk in the Trunk | 5c | 5.9 | 23 m | Fisher Valley | theCrag 2 stars |
| Face to Face | 5c | 5.9 | 12 m | Fisher Valley | theCrag 1 star |
| Flying Squirrel | 6a | 5.10a | 20 m | Fisher Valley | theCrag 2 stars |
| Mechanic Hands | 6a | 5.10a | 27 m | Fisher Valley | theCrag 2 stars |
| Dark Dihedral | 6a | 5.10a | 11 m | Hidden Valley | theCrag 1 star |
| Slingswing | 6a | 5.10a | 18 m | The Cave | theCrag 2 stars |
Intermediate: 6a+ to 6c+ (YDS 5.10b–5.11c)
Fisher Valley's intermediate tier is concentrated in the long routes near 6c (30 to 38 m), while Hidden Valley has short routes and slabs from 6b to 6c+.
| Route | Grade | YDS | Length or pitches | Sector | Notes |
|---|---|---|---|---|---|
| Moustache Massage Man | 6a+ | 5.10b | 8 m | Butterfly Valley | theCrag 1 star |
| Unobbtainable HR | 6a+ | 5.10b | 12 m | Butterfly Valley | theCrag 2 stars |
| Intrigues | 6a | 5.10a | 28 m | Butterfly Valley | no stars on theCrag |
| Dublin Mudslide | 6a | 5.10a | 25 m | Butterfly Valley | theCrag 1 star |
| The Grass Is Always Greener | 6b | 5.10c | 23 m | Butterfly Valley | theCrag 2 stars |
| Very Tot | 6b+ | 5.10d | 21 m | Butterfly Valley | theCrag 2 stars |
| Fingerless Pho Man | 6c+ | 5.11c | 20 m | Butterfly Valley | theCrag 2 stars |
| Miyagi Box Maker | 6c+ | 5.11c | 20 m | Butterfly Valley | theCrag 3 stars |
| Bolts 'R' us | 6c+ | 5.11c | 16 m | Butterfly Valley | theCrag 3 stars |
| Cracker Jack | 6c | 5.11a/b | 21 m | Butterfly Valley | theCrag 2 stars |
| Over the Moon | 6a+ | 5.10b | 23 m | The Cave | theCrag 2 stars |
| Breakout | 6b+ | 5.10d | 18 m | The Cave | theCrag 2 stars; can still be wet after rain |
| Namastay on the wall | 6b+ | 5.10d | 17 m | The Cave | theCrag 3 stars |
| Srew You | 6b | 5.10c | 20 m | Hidden Valley | theCrag 2 stars |
| Nesto's Gift | 6b | 5.10c | 18 m | Hidden Valley | theCrag 3 stars |
| Bozo's Big Day | 6b | 5.10c | 21 m | Hidden Valley | theCrag 2 stars |
| Ich Will In Dich Sein | 6a+ | 5.10b | 18 m | Hidden Valley | theCrag 2 stars |
| House of Jugs | 6c | 5.11a/b | 17 m | Hidden Valley | theCrag 3 stars |
| Which Way To The Beach | 6c+ | 5.11c | 15 m | Hidden Valley | theCrag 2 stars |
| Kenzie Town | 6a+ | 5.10b | 20 m | Fisher Valley | theCrag 2 stars |
| Butchered Olives | 6a+ | 5.10b | 18 m | Fisher Valley | theCrag 2 stars |
| Liv to Climb Another Day | 6b | 5.10c | 23 m | Fisher Valley | theCrag 3 stars |
| Careful, She Bites! | 6b+ | 5.10d | 20 m | Fisher Valley | theCrag 2 stars |
| Spender Bender | 6b+ | 5.10d | 24 m | Fisher Valley | theCrag 1 star |
| River of Strength | 6b | 5.10c | 24 m | Fisher Valley | theCrag 1 star |
| Eternal Squanch | 6c | 5.11a/b | 35 m | Fisher Valley | theCrag 3 stars |
| Hernadez the Hernia | 6c+ | 5.11c | 30 m | Fisher Valley | theCrag 2 stars |
| Iron Lion | 6c+ | 5.11c | 24 m | Fisher Valley | theCrag 2 stars |
| Convoluted Corner | 6c | 5.11a/b | 16 m | Fisher Valley | theCrag 3 stars |
| Ants Marching Left | 6c | 5.11a/b | 38 m | Fisher Valley | theCrag 2 stars; paired with Ants Marching Right |
Advanced: 7a to 7c+ (YDS 5.11d–5.13a)
Butterfly Valley has the most routes in the 7s (more than 20), Fisher Valley is concentrated from 7a to 7c+, and Hidden Valley's own description singles out overhanging roof climbs — Shampoo Effect is the sector's signature route.
| Route | Grade | YDS | Length or pitches | Sector | Notes |
|---|---|---|---|---|---|
| My Way | 7a+ | 5.12a | 18 m | Butterfly Valley | theCrag 2 stars |
| Team Ling Ling | 7a+ | 5.12a | 28 m | Butterfly Valley | theCrag 3 stars, 14 bolts |
| Buffalo Love | 7a+ | 5.12a | 26 m | Butterfly Valley | theCrag 3 stars, 15 bolts |
| Pappi's Paradise | 7a | 5.11d | 28 m | Butterfly Valley | theCrag 2 stars, 14 bolts |
| Obama 101 | 7a | 5.11d | 20 m | Butterfly Valley | theCrag 2 stars, 12 bolts |
| Up Syndrome | 7a | 5.11d | 20 m | Butterfly Valley | theCrag 2 stars, 13 bolts |
| Windchime of the Ants | 7a | 5.11d | 28 m | Butterfly Valley | theCrag 2 stars, 13 bolts |
| Thanks For The Memories | 7b | 5.12b | 31 m | Butterfly Valley | theCrag 3 stars, 15 bolts |
| Pole Dancer | 7b | 5.12b | 22 m | Butterfly Valley | theCrag 3 stars, 9 bolts |
| Chia Tay | 7b | 5.12b | 20 m | Butterfly Valley | theCrag 1 star, 12 bolts |
| Prayer Of The Mantis | 7b | 5.12b | 20 m | Butterfly Valley | theCrag 3 stars, 11 bolts |
| Freakonomics | 7b | 5.12b | 27 m | Butterfly Valley | theCrag 3 stars, 13 bolts |
| Hippie Banana Tree Killer | 7b+ | 5.12c | 25 m | Butterfly Valley | theCrag 3 stars, 13 bolts |
| Passive Aggressive | 7b+ | 5.12c | 21 m | Butterfly Valley | theCrag 1 star, 11 bolts |
| Year of the Tiger | 7c | 5.12d | 26 m | Butterfly Valley | theCrag 2 stars, 12 bolts |
| Dream Weaver | 7c+ | 5.13a | 22 m | Butterfly Valley | theCrag 3 stars, 13 bolts |
| Horseless Samurai | 7c+ | 5.13a | 27 m | Butterfly Valley | theCrag 3 stars, 15 bolts |
| Monarch | 7c+ | 5.13a | 25 m | Butterfly Valley | theCrag 3 stars, 13 bolts |
| Fistful of Stalactite | 7a+ | 5.12a | 17 m | The Cave | theCrag 3 stars |
| Chó cái for life | 7a | 5.11d | 17 m | The Cave | theCrag 3 stars |
| Mr Zoom | 7c/c+ | 5.12d | 10 m | The Cave | theCrag 3 stars; the shortest and hardest route in the cave |
| Test Pilot | 7a | 5.11d | 22 m | Hidden Valley | theCrag 2 stars, 12 bolts |
| Monocle Man | 7a+ | 5.12a | 16 m | Hidden Valley | theCrag 3 stars, 11 bolts |
| Shampoo Effect | 7b+ | 5.12c | 17 m | Hidden Valley | theCrag 3 stars; roof route |
| Power & Good Vibes | 7b | 5.12b | 13 m | Hidden Valley | theCrag 2 stars |
| Next Time Get It | 7b | 5.12b | 26 m | Hidden Valley | theCrag 2 stars, 14 bolts |
| Bird Snake | 7a | 5.11d | 30 m | Fisher Valley | theCrag 1 star, 12 bolts |
| Root Vine | 7a | 5.11d | 38 m | Fisher Valley | theCrag 3 stars, 14 bolts |
| Tesco ya Slut | 7a | 5.11d | 40 m | Fisher Valley | theCrag 2 stars, 15 bolts |
| Formic Acid | 7a+ | 5.12a | 24 m | Fisher Valley | theCrag 3 stars, 10 bolts; roof section |
| Kangaroo Jack | 7a+ | 5.12a | 18 m | Fisher Valley | theCrag 2 stars |
| Indispensable Knowledge | 7b | 5.12b | 28 m | Fisher Valley | theCrag 2 stars, 8 bolts |
| Tampon Finger Joe | 7c | 5.12d | 27 m | Fisher Valley | theCrag 3 stars, 9 bolts |
| Lipstick on a Pear | 7c+ | 5.13a | 30 m | Fisher Valley | theCrag 3 stars, 12 bolts |
Expert: 8a and up (YDS 5.13b and up)
Butterfly Valley has the hardest routes on the island, but it also has the oldest bolt condition — read the two together.
| Route | Grade | YDS | Length or pitches | Sector | Notes |
|---|---|---|---|---|---|
| My Way Or The Railway | 8a | 5.13b | 28 m | Butterfly Valley | theCrag 3 stars, 13 bolts |
| Butterfly Effect | 8a | 5.13b | 12 m | Butterfly Valley | theCrag 3 stars, 10 bolts |
| Enter The Dragon | 8a+ | 5.13c | 35 m | Butterfly Valley | theCrag 3 stars, 14 bolts |
| Roman's Karmic Curse | 8a+ | 5.13c | 17 m | Butterfly Valley | no stars on theCrag, 10 bolts |
| Guerrero Argentino | 8c+/9a | 5.14c | 25 m | Butterfly Valley | no stars on theCrag, 14 bolts; hardest on the island |
| El Loco Bee | 8a+/b | 5.13c | 8 m | The Cave | theCrag 1 star, 4 bolts; short burst route in the cave |
Bouldering
The small bouldering cave in Hidden Valley has five problems; theCrag lists V grades directly, with no Font grades to convert.
| Route | V grade | Sector | Notes |
|---|---|---|---|
| Fat Santa | V1 | Hidden Valley | 4 m |
| Total Eclipse Of The Heart | V3 | Hidden Valley | 4 m |
| Under The Bridge | V6 | Hidden Valley | 4 m |
| Scotch Mist | V6 | Hidden Valley | 4 m |
| Around The World | V7 | Hidden Valley | 4 m, theCrag 3 stars |
Trad
| Route | Original grade | YDS | Length or pitches | Wall | Notes |
|---|---|---|---|---|---|
| Firefly | 5.11 | 5.11 | — | Butterfly Valley | theCrag 1 star; the original grade is already YDS, so it is not converted again |
| Approach to Trad | 5b | 5.8 | 8 m | Butterfly Valley | theCrag 2 stars; short sport route linking to the trad section |
Where to look things up
- theCrag: Cat Ba Island: the index of 178 routes, the access rules for the island, the current state of gear rental, and history.
- theCrag: Fisher Valley, Hidden Valley, Butterfly Valley, The Cave, Ben Beo Harbour: approaches, permit prices, fixed-point warnings and development history for each sector.
- Cat Ba Climbing: trip and transfer prices, rental gear in Cat Ba, and how each area has been run since 2016. Their office is at 120 Nui Ngoc Street in Cat Ba town, WhatsApp +84 347645000.
- Langur's Adventures: where to get the Butterfly Valley permit, and half-day trips in sport climbing and deep water soloing (DWS), 1,300,000 VND each.
- Guidebook: Grades and route counts here come mainly from online databases; the guidebook is the authority.
- 《Vietnam Climbing》, Luca De Giorgi and Gavi Piper, second edition 2023, 230 pages, ISBN 9781727545128, in English. Sport climbing and deep-water bouldering in Ha Long Bay and Cat Ba Island are the core of the book, and it comes with a Vertical-Life app redemption code.
- A copy of 《Vietnam Climbing》 is also sold locally on Cat Ba, 600,000 VND in the Cat Ba Climbing shop; the product description gives it as the 2018 edition covering Ha Long Bay / Lan Ha Bay / Cat Ba Island, while theCrag's Lan Ha Bay page describes a guidebook for the same area published in 2016, 140 pages. The two descriptions do not agree on the edition, so go by the physical copy before you buy.
References
- theCrag: Cat Ba Island
- theCrag: Fisher Valley
- theCrag: Hidden Valley / The Farm
- theCrag: Butterfly Valley
- theCrag: The Cave / Buddha Cave
- theCrag: Ben Beo Harbour
- Cat Ba Climbing, Langur's Adventures
- UK travel advice: Getting help in Vietnam
- Wikipedia: Hanoi (climate table)
- Mountain Project international grade comparison