By Adele Marchetti · Sep 17, 2026 · 7 min
The Apostle Islands look like an easy answer to a hard question: island camping, cliffs, sea caves, a short drive from the Midwest. Then you read the water temperature. Lake Superior's surface only reaches the 50s and 60s Fahrenheit at the height of summer, and the crossings between islands run several miles of open water each.
Trip length is genuinely up to you — often 20 to 50-plus miles — because the National Park Service does not publish a numbered route for the crossing. What the park does publish is exact GPS coordinates for every island campsite, and that list, not a route line, is what you plan your nights from.
Why cold water outranks distance here
Hypothermia in minutes is the phrase that should govern this trip, in July as much as in May. Squalls build fast and produce steep, close-spaced waves, and fog can erase the island you were aiming for. The mainland sea caves are spectacular and are only safe in settled conditions; falling rock and ice at the caves are part of the hazard picture, not a rare event.
Behind the outer islands there are long dead zones with no cell coverage. The habit that keeps parties safe is checking the NOAA marine forecast for western Lake Superior before every crossing — not every morning, every crossing.
Permits, bears and the small stuff that decides trips
A wilderness camping permit is required for every overnight stay in the national lakeshore, reserved in advance through Recreation.gov. Day paddling the mainland caves needs no permit; every island night does.
The islands hold one of the highest black-bear densities in the region. Use the park's bear lockers or a canister — this is not a hang-a-bag situation. Biting stable flies are the other local specialty, and they are unbothered by repellent. Piping plover nesting beaches close seasonally, so confirm closures before planning a landing.
Water is clear and still needs filtering or treatment for Giardia and Cryptosporidium.
The season, honestly
Late June to early September is the window. Ice can linger into May, with water near freezing and unpredictable weather. September and October are gale season — fast-building high-wind events and cold rain, beautiful and serious in equal measure. November through March the lake ices over and paddling is not possible.
Three trips, in rising order of exposure
The sea caves weekend is two days: Meyers Beach to Sand Island and back, with the mainland caves, the Sand Island light and one reserved island campsite. It is the least committing way to feel what this lake does.
The Sand Island base camp adds a day and subtracts risk in an underrated way — cross once from Meyers Beach, camp two nights, and day-paddle the sea caves and lighthouse shore without moving camp or making further long crossings. When the forecast is mixed, this is the smart version of the trip.
The outer ring is five days from Little Sand Bay out to Oak, Stockton and Rocky islands: longer crossings, real Lake Superior weather, and the trip that earns the ranking.
Plan it as a cold-water sea trip that happens to be in Wisconsin, and build a spare day into the schedule for the day the lake says no.