Ask whether the Kandy waterdrome (KDY) has a lounge, and the honest short answer is no: this is a seaplane base on the Mahaweli River, Sri Lanka's longest river, rather than an airline terminal, and nothing resembling passenger lounge infrastructure exists at the jetty where floatplanes dock in the hill country near Kandy.
The reality on the ground explains that better than any comparison of size could. Seaplanes land directly on the Mahaweli River and taxi to a floating jetty, where passengers step from pontoon to shore with no terminal building, no security hall, and no waiting lounge in between. Most travellers using this route are moving quickly between a scenic flight and Kandy's hill-country sights, the Temple of the Sacred Tooth Relic and Kandy Lake among them, rather than settling in for a long pre-flight wait, and the whole visit is built around the scenery rather than an airport experience.
For genuine lounge access connected to a Sri Lanka itinerary, Bandaranaike International Airport (CMB) near Colombo is the country's real gateway. CMB carries the island's actual lounge infrastructure, airline lounges for premium-cabin and elite-status passengers alongside broader card-network coverage, in a way a river jetty built for scenic seaplane hops was never meant to offer. Confirm specific lounge access and hours with your airline or card program before you fly, since terms at a hub like CMB can shift over time, and do not expect the same arrangements to apply once you leave Colombo for the hill country.
Treat the Kandy waterdrome as a genuinely scenic link between Colombo and the hill country, not a stop where lounge planning makes sense. If your trip pairs a seaplane hop to Kandy with an international flight through Colombo, build any lounge time into the CMB end of the journey and confirm your Kandy transfer directly with the seaplane operator instead, since the jetty itself was never built around a passenger wait, only a quick and scenic handoff between river and road.