Mikołajki sits on a narrow neck of land between Lake Mikołajskie and Lake Tałty, and just south of it the huge, shallow expanse of Śniardwy opens out, the biggest lake in Poland. Everything here is water. The glaciers that scoured this part of the north-east left a maze of lakes joined by channels and rivers, and the town grew up as a fishing village where two of them touch. Today it calls itself the sailing capital of Masuria, and in July the harbour is a thicket of masts.
The best reason to swim here is that the lake is so unhurried. Water is shallow near the shore, warm by August, and clear enough that you see your feet. Public bathing spots are scattered around the town, along with the lakeside promenade and the old bridges that open for the passing yachts. A bronze whitefish king sits near the water, a bit of cheerful local mythology about a monarch of the fish who wore a crown, and children climb on it without apology. Fish is the thing to eat. Smoked eel, fried perch and pike-perch turn up on every menu, and the smoked varieties are sold from stalls near the quay.
Just a few kilometres away lies Łuknajno, a small lake that is a biosphere reserve and one of the best places in Europe to see mute swans in large numbers. It is a protected area, so you look from the edge and leave it alone. Cormorants, herons and cranes are common all across the region, and in the evening the call of a crane over reeds can stop a conversation.
The roads in the area are good, flat to gently rolling and often lined with old lime and chestnut trees that arch over the tarmac. They are lovely, but they are also full of tractors, delivery vans and holiday traffic on summer weekends, so treat them as a pleasant cruise rather than a challenge. Watch for deer at dusk and for speed cameras in the villages, where fifty means fifty. Mikołajki is large enough to have fuel stations and shops, and Mrągowo, a larger town about nineteen kilometres off, is the fallback. Come in June or early September if you can, when the lake is warm but the boardwalks are not yet shoulder to shoulder.