Go canyoneering at Kawasan Falls. This is Cebu's signature adventure — a 3-4 hour guided route of jumping, swimming and floating down turquoise canyon pools near Badian, ending at the falls. Tours with gear and guide cost roughly ₱1,500-₱2,500 ($24-$40), plus transport from Cebu City (about 3 hours each way). You need basic fitness but not swimming expertise; life jackets are mandatory.
Snorkel the Moalboal sardine run. Millions of sardines swirl just metres off Panagsama Beach, with sea turtles grazing nearby. It is shore-accessible, cheap and one of the best free-diving sights in Asia.
Island-hop from Mactan. Day tours cover islets like Nalusuan and Caohagan with sandbars and reef stops, usually with a grilled seafood lunch on board. Group tours run about ₱1,500-₱2,500 ($24-$40) per person.
See the city's history. Magellan's Cross, the Basilica del Santo Niño and Fort San Pedro sit within walking distance of each other and cover 500 years of history in a couple of hours. Add the hilltop Temple of Leah and Sirao flower garden for sunset views over the city.
If you have a spare day, the Bohol day trip — Chocolate Hills and tarsiers — is a fast 2-hour ferry away and easy to book as a package.