Across Chetumal Bay from Corozal, the largely uninhabited Sarteneja peninsula is covered with dense forests and swamps that support an amazing array of wildlife. The only village is SARTENEJA , a quiet, Spanish-speaking lobster-fishing centre. A couple of new hotels have been built (there's also accommodation at the reserve), and guides are available to take you to the lagoons and beyond. The best place is Fernando's Seaside Guest House (tel 423-2045; US$25-40), on the seafront, which has thatched rooms with private bath and a restaurant. The Northern Transport bus to Sarteneja from Belize City leaves at noon and 1.30pm; the Venus bus to Sarteneja departs at 12.30pm (both Mon-Sat; 4hr; US$6), stopping at Zeta's store on Main St in Orange Walk ninety minutes later. Buses return from Sarteneja at 5am and 6am.

The Shipstern Nature Reserve (daily 8am-5pm; US$5 including guided walk), established in 1981, covers an area of eighty square kilometres. The bulk of the reserve is made up of what's technically known as "tropical moist forest", and includes some wide belts of savanna - covered in coarse grasses, palms and broad-leaved trees - and a section of the shallow Shipstern Lagoon, dotted with mangrove islands. Taking the superb guided walk along the Chiclero Trail , you'll encounter more named plant species in an hour than on any other trail in Belize. Shipstern is also a bird-watcher's paradise: the lagoon system supports blue-winged teal, American coot, and huge flocks of lesser scaup, while the forest is home to fly-catchers, keel-billed toucans and at least five species of parrot. Other wildlife in the reserve includes crocodiles, coatis, jaguars, peccaries, and an abundance of wonderful butterflies.

All buses to Sarteneja pass the entrance to the reserve, 5km before the village. You can stay at the headquarters near the visitor centre, where there are two neat four-bed dorms (US$10 per person) with cooking facilities, and a two-roomed house for rent (US$40).