Cockscomb Basin Wildlife Sanctuary sits about 30 km inland from Hopkins, in the foothills of the Maya Mountains. It is the world's first jaguar preserve and still one of the best-protected wild jaguar habitats in Central America. Seeing a jaguar in daylight is genuinely unlikely — they are nocturnal and avoid people — but the sanctuary is excellent for birdwatching (over 150 species recorded), and the forest itself is beautiful: tall broadleaf lowland rainforest with clear streams running through it.
The trail network is well-maintained. The main loop past the waterfall and river swimming hole is manageable in half a day. The Victoria Peak trail, climbing to Belize's highest point at 1,120 metres, is a multi-day undertaking requiring a guide and permit, but it's one of the more demanding and rewarding hikes in the country. Day trips from Hopkins work well for the easier trails — arrange with a tour operator in the village or drive yourself on the well-signposted turnoff from the Southern Highway. The entry fee is modest and goes directly toward sanctuary management.