Island hopping or interesting day trips from the south coast?

From the south: Pigeon Island (near Trinco, better as overnight), but closer options include small islands off Hikkaduwa for snorkeling, or day trips to Kanneliya rainforest or the temples around Galle. Some people do day trips to Colombo for shopping or museums. For a real change of scene, a day trip to the hill country (Ella area) is possible but long. Most visitors are happy staying on the coast and doing short boat trips or inland temple visits rather than true 'island hopping'.