Bonifacio

Three options. Walk: about 15 minutes uphill on Avenue Charles de Gaulle, gentle but steady, no shade in summer. Navette: a small electric shuttle bus runs from the marina up to Porte de Genes (the old town gate) for a couple of euros each way. Petit train: the tourist train loops marina-to-haute-ville with commentary if you want to be driven. The Escalier du Roi d'Aragon staircase goes the other direction — down the cliff to the sea — and is for sightseeing, not a practical way up.

If you have decent knees, yes — and only if you remember it is 187 steep, uneven, often slippery steps cut into a limestone cliff, and you have to come back up the same way. The view halfway down is the postcard you have already seen. There is a small entry fee. People with hip or balance issues should skip it; the same view from the haute ville ramparts is free and requires no negotiation with gravity.

Yes — small operators run hour-long cliff-and-grotto tours from the marina (the Sdragonato sea cave with its cross-shaped opening is the standard stop), and longer half-day excursions to the Lavezzi archipelago for swimming and snorkeling. Lavezzi trips are weather-dependent; the Bouches de Bonifacio get rough fast in the prevailing winds, and operators will cancel rather than fight the chop. Book at the marina kiosks on arrival; do not commit before you have seen the sea state.

Realistically, no. There is a passenger ferry across to Santa Teresa Gallura that takes about an hour each way, but the schedule is not built around cruise tender windows, and you would spend most of your call in transit. If you want to stand in Sardinia, do it on a separate trip. From the haute ville ramparts you can see it perfectly well, which is most of what people actually want.

The cruise season runs roughly April through October, peaking in June-September. Outside that window the haute ville stays open but a noticeable share of the cafes, boat operators, and the navette shuttle wind down or run reduced hours. The wind also picks up — the Bouches de Bonifacio are one of the windiest stretches in the Mediterranean, and shoulder-season tender cancellations happen.

French. Corsican is spoken among locals and you will see it on signage alongside French, but you do not need it. English is workable in the marina restaurants and most haute-ville shops, less so in smaller cafes. Currency is euro; cards are accepted almost everywhere, but the Escalier entry, the navette, and small market stalls in the old town are easier with a few coins on hand.