The blue whale watching from Mirissa is among the best in the world. The deep water south of the bay is home to a resident population of blue whales year-round, and between November and April conditions are calm enough for regular boat trips. Sperm whales, Bryde's whales, and several species of dolphin are also commonly seen on these trips.
Most operators run morning departures from the harbour, setting off before sunrise and returning by midday. The trips last four to five hours. Success rates during peak season (January to March) are high but never guaranteed. Book through a reputable operator rather than the first person who approaches you on the beach — standards vary. Bring sunscreen, seasickness tablets if you are susceptible, and something warm for the early-morning departure.