A big limestone cave in the Monti Ernici, in the province of Frosinone in southern Lazio. The databases list 31 to 67 routes starting at 6b, most of them 7a and up, and Laura Rogora made the first ascent of several top-end lines here, including Rèveille-toi 9a. The cave is shaded all day and climbable in heavy rain. What changes your plans most is the closure: every source says the whole Collepardo climbing area is closed from 1 January to 31 July for nesting raptors. No primary notice was found, so in practice you can only go from August to December, best from September to November. You need a car.
A single-pitch sport crag in the Valle del Salto, southeast of Rieti in northern Lazio. The rock is pocketed limestone shading into conglomerate; the databases list 161 to 255 routes, most of them 7a and up, topped by Ultimo Tango a Zagarolo 9a/+ (first ascent 2020). There are only a dozen or two routes at 6a and below, so it is not a beginner crag. The walls face south: November to March is best, and in summer you climb only in the evening. Without a car you can take Cotral's Contigliano–Rieti–Avezzano line to the Grotti stop, but there are very few buses.
Two seaside crags at Gaeta, at the southern tip of Lazio. Grotta dell'Arenauta is a steep limestone cave behind a sand dune, listed at 30–56 routes depending on the site, mostly 7a and up, topping out at L'Arenauta 9b (2022), and climbable in the rain. Montagna Spaccata is sea-cliff multi-pitch reached by abseil or boat, up to about 120 m; falesia.it says it is open only from 1 August to 20 February. Take the train to Formia-Gaeta and a Cotral bus into town; for the cave you need a car or a hired driver.
Limestone walls behind the Sant'Agostino plain on the southern Lazio coast, between Sperlonga and Gaeta. Climbers call them "Sperlonga", but they sit inside the Itri and Gaeta municipal boundaries. theCrag lists 424 routes and falesia.it's Monte Moneta page another 206, nearly all single-pitch sport. The walls face roughly south; Climbing Spot Factory gives October to May as the best months, and summer is too hot. The meeting point is Ristoro da Guido on the SS Flacca; there is no direct public transport, so a car is easiest.