A bustling farming community once thrived on Grenadier Island, but today it’s mostly the summer people who remain. The bustle of activity on the island is now made by boaters, hikers and paddlers who fancy the warm sandy beaches, old fishing holes, vivid past, and abundant opportunities for observing wildlife.

If the weather is fair, a circumnavigation of Grenadier Island is a splendid full-day paddle that brings you past extensive marshlands alive with noisy red-wing blackbirds, blue herons stalking prey, and perhaps an osprey circling overhead.

Several landing points along the shores of Grenadier Island allow you to rest or stretch your...