Madu River by Catamaran

Just inland from the south-coast resorts, the Madu Ganga opens into a maze of mangrove channels and small islands — a quiet, green world that most travellers skim straight past on the highway.

Hire a boat at Balapitiya in the early morning. The channels narrow until the mangroves close overhead into tunnels, then open onto a lagoon dotted with islands, one of them home to a tiny island temple reached only by water. Kingfishers, monitor lizards and water birds are everywhere if you keep quiet.

It is a half-day at most, but it is the gentlest, most restful half-day on the south coast.