Sri Lanka sits at the convergence of deep oceanic channels that bring some of the planet’s most magnificent marine mammals close to its southern shores, making the waters off Mirissa and Trincomalee among the finest whale-watching locations anywhere in the world. Blue whales – the largest animals to have ever lived on earth – are sighted with regularity between November and April, often close enough for their sheer scale to be genuinely awe-inspiring. Pods of spinner and bottlenose dolphins frequently escort boats in playful formation, leaping and spinning across the bow in a display of effortless grace.