Maine has over 6,000 lakes and ponds. Finding a place to swim is not the problem. Finding the right place is. Some lakes have sandy beaches and lifeguards. Others have granite ledges and total solitude. Some are so clean they serve as drinking water without filtration. Here are the 15 that are actually worth planning a day around.
Quick picks: Cleanest water: Sebago | Warmest: Long Lake | Most scenic: Echo Lake | Best state park beach: Lake Webb | Most underrated: Lake St. George | Best near Portland: Sebago
| Lake | Region | Temp | Beach | Fee | Best For |
|---|---|---|---|---|---|
| Sebago Lake | Lakes Region | Cool | Sand | $8 | Crystal-clear water |
| Moosehead Lake | North Woods | Cold | Sand | Free/$8 | Wilderness setting |
| Rangeley Lake | Western Mtns | Cool | Sand | $8/Free | Mountain views |
| Echo Lake | Acadia | Warm-ish | Sand | Park pass | Scenic swim |
| Thompson Lake | Oxford | Cool | Sandy bottom | Free | Clean + quiet |
| Long Lake | Naples | Warm | Sand | Free | Social beach day |
| Damariscotta Lake | Midcoast | Moderate | Sand | $8 | Uncrowded |
| Lake St. George | Midcoast | Warm | Sand | $8 | Hidden gem |
| Branch Lake | Ellsworth | Cool | Sand + dock | Free | Near Acadia |
| Great Pond | Belgrade | Warm | Sand | Free | Classic Maine lake |
| Kezar Lake | Lovell | Cool | Sand | Free | Mountain backdrop |
| China Lake | Central ME | Warm | Sandy bottom | Free | Quick warm-up |
| Clearwater Lake | Farmington | Moderate | Sand | Free | Name says it all |
| Lake Webb | Weld | Cool | Sand | $8 | Beach + mountains |
| Megunticook Lake | Camden | Moderate | Sand | Free | After a hike |
1. Sebago Lake
Location: Standish/Casco/Naples | Size: 28,771 acres | Max Depth: 316 ft
Sebago is the one everyone talks about, and for once the hype is earned. The water is so clean it serves as Portland’s drinking supply without filtration. That is not a marketing claim. The city pulls water directly from the lake and sends it to taps. On a sunny day the visibility is startling. You can see your feet in chest-deep water.
Sebago Lake State Park has two sand beaches with lifeguards in summer. The Casco side beach tends to be quieter than the Naples side, which draws a younger, louder crowd on weekends.
Swimming access: Sebago Lake State Park (day use fee $8/adult).
2. Moosehead Lake
Location: Greenville | Size: 74,890 acres | Max Depth: 246 ft
Maine’s largest lake. Not by a little. Moosehead is so big it has its own weather patterns and a mountain, Kineo, rising straight out of the water. Swimming here is a cold-water commitment. Even in August the temperature hovers in the low 60s. But on a hot day, the combination of mountain backdrop, forest shoreline, and sheer scale makes every other lake feel small.
The Greenville town beach is free and fine for a quick dip. Lily Bay State Park, about 8 miles north, has a longer sandy beach and more room to spread out.
Lily Bay State Park is worth the drive past Greenville. The beach is bigger, the water is slightly warmer in the shallow cove, and there are far fewer people. Camp here if you can. The sites right on the water are some of the best in the state.
3. Rangeley Lake
Location: Rangeley | Size: 6,000 acres | Max Depth: 149 ft
Rangeley feels remote. Mountains surround the lake on all sides, dense forest runs to the shoreline, and the town of Rangeley has about 1,200 year-round residents. The state park beach has a gentle sandy entry that slopes gradually. Kids can wade out 30 feet and still be knee-deep.
Swimming access: Rangeley Lake State Park ($8/adult) or the free town beach near the boat launch. The state park is better for swimming. The town beach is better for quick access.
4. Echo Lake, Acadia National Park
Location: Mount Desert Island | Size: 237 acres | Max Depth: 66 ft
Echo Lake is Acadia’s answer to the question “where can I actually swim without a wetsuit?” The ocean at Sand Beach rarely cracks 55 degrees. Echo Lake, tucked between Beech Mountain and Acadia Mountain, warms into the low 70s by mid-July. A small sand beach with a lifeguard sits at the south end.
The mountains framing the lake make this possibly the most scenic lake swim in Maine. The tradeoff is parking, which fills early. Arrive before 10 AM or take the Island Explorer shuttle.
5. Thompson Lake
Location: Oxford/Casco/Otisfield | Size: 4,400 acres | Max Depth: 118 ft
Thompson flies under the radar because it does not have a state park or a famous town on its shore. That is the appeal. The water is consistently ranked among the clearest in southern Maine, with a slight blue tint on sunny days and a sandy bottom that makes wading comfortable. Several informal access points and camp beaches provide entry. The public boat launch in Oxford has a small swim area.
A locals’ lake. Not a tourist destination. That is a compliment.
Lakes Near Portland
If you are based in the Portland area and want to swim without a long drive, these are your best options:
- Sebago Lake (45 min) is the premier choice. Clean, cold, beautiful.
- Highland Lake in Bridgton (50 min) is smaller and warmer, with a free town beach.
- Range Pond State Park in Poland (35 min) has a sand beach and is the closest state park swim to Portland.
- Mackworth Island in Falmouth (10 min) is saltwater, not a lake, but worth mentioning for its proximity.
6. Long Lake
Location: Naples/Bridgton/Harrison | Size: 5,052 acres | Max Depth: 62 ft
Long Lake is the social lake. The Causeway Beach in Naples sits right in town, surrounded by shops, restaurants, and the Songo River Queen paddleboat. On a Saturday in July it feels like a beach town anywhere on the east coast, just with mountains instead of ocean.
The water is warmer than most Maine lakes because it is relatively shallow. Sandy beach, easy access, free parking. If you want a lively beach day rather than wilderness solitude, this is the pick.
7. Damariscotta Lake
Location: Jefferson/Nobleboro/Newcastle | Size: 4,381 acres | Max Depth: 114 ft
Damariscotta Lake State Park is the beach that Midcoast locals do not want you to know about. Excellent water clarity, shaded picnic area under tall pines, sand beach that slopes gently into the water. It rarely feels crowded, even on summer weekends. The lake warms up nicely by mid-July.
Swimming access: Damariscotta Lake State Park ($8/adult).
8. Lake St. George
Location: Liberty | Size: 1,017 acres | Max Depth: 63 ft
Ask someone from away to name a Maine swimming lake and they will never say Lake St. George. Ask someone from the Midcoast and they will grin. The state park beach is well-maintained with a roped swim area, picnic tables under tall pines, and water that warms up fast from late June on. The surrounding area feels unhurried and uncommercial in a way that bigger lakes have lost.
Swimming access: Lake St. George State Park ($8/adult).
Cleanest Lakes in Maine
Water clarity matters for swimming, and Maine tests its lakes regularly. The consistently cleanest include:
- Sebago Lake serves as Portland’s unfiltered drinking water supply. That tells you everything.
- Thompson Lake regularly posts some of the highest Secchi disk readings (a measure of transparency) in southern Maine.
- Branch Lake supplies Ellsworth’s drinking water and is carefully protected.
- Kezar Lake is deep, spring-fed, and strikingly clear, with visibility often exceeding 20 feet.
Check the Maine DEP’s annual lake water quality report for the latest data on any lake you plan to visit.
9. Branch Lake
Location: Ellsworth | Size: 2,987 acres | Max Depth: 123 ft
Branch Lake is Ellsworth’s drinking water supply, which means it is carefully protected and exceptionally clean. The town beach has a sandy shoreline and a dock for jumping. Being just 15 minutes from Acadia, it makes a perfect complement to a day of hiking or coastal sightseeing. The water is cleaner than most and the crowd is mostly local families.
Swimming access: Branch Lake Public Beach (free).
10. Great Pond, Belgrade Lakes
Location: Belgrade/Rome | Size: 8,239 acres | Max Depth: 69 ft
The Belgrade Lakes chain has been a summer destination since the 1800s. Great Pond is the largest of the group, with clean water, warm temperatures, and a shoreline dotted with classic Maine lake cabins. The area inspired “On Golden Pond” (though the film was shot in New Hampshire, a fact Mainers will correct you on).
Belgrade town beach on West Road is free. Grab lunch in Belgrade Lakes village afterward. The general store has sandwiches and ice cream that taste better when you are still drying off.
11. Kezar Lake
Location: Lovell | Size: 2,525 acres | Max Depth: 154 ft
Kezar is deep, clear, and surrounded by the White Mountain foothills with almost no shoreline development. The water has a blue tint that photographs beautifully. The public beach at the north end has mountain views in every direction. Parking is limited, which keeps the crowd small. Get there early on weekends.
Swimming access: Kezar Lake public beach in Lovell (free, limited parking).
Kezar’s depth means it stays cool even in August. The shallow southern end warms up faster. If you want the warmest water, swim from the south shore access points rather than the north beach.
12. China Lake
Location: China/Vassalboro | Size: 3,845 acres | Max Depth: 85 ft
China Lake made a strong comeback from water quality issues in the 1990s. The conservation effort worked, and the swimming is once again excellent. The town beach in China village has a sandy bottom and a relaxed, uncommercial atmosphere. Because it is relatively shallow on average, it warms up quickly, making it one of the first swimmable lakes each season.
Swimming access: China Lake public beach (free).
13. Clearwater Lake
Location: Industry/Farmington | Size: 721 acres | Max Depth: 62 ft
The name is not aspirational. The lake is genuinely clear. A small, clean lake in Franklin County with a well-maintained town beach, sandy bottom that extends well out from shore, and surrounding hills that keep the wind down. It is the kind of place where you set up a blanket in the morning and do not move until dinner.
Swimming access: Town beach off Clearwater Lake Road (free).
14. Lake Webb
Location: Weld | Size: 2,569 acres | Max Depth: 109 ft
Mount Blue State Park, on the shore of Lake Webb, has one of the best state park beaches in Maine. The sandy beach is large, the water is clean, and Tumbledown Mountain rises behind the far shore. It is a long drive from the coast, which is exactly why it never feels overcrowded. The combination of lake swimming and mountain scenery is hard to beat anywhere in the state.
Swimming access: Mount Blue State Park ($8/adult).
15. Megunticook Lake
Location: Camden/Lincolnville/Hope | Size: 1,274 acres | Max Depth: 63 ft
Camden is famous for its harbor, but Megunticook Lake, just inland, is where locals actually go to swim. Barrett Cove Memorial Park has a public beach with clear water and views of the surrounding hills. After a swim, you are a short drive from downtown Camden, the harbor, and the coast. A good pairing with a morning hike up Mount Battie.
Swimming access: Barrett Cove Memorial Park, Lincolnville (free).
Tips for Lake Swimming in Maine
Water temperature: Most Maine lakes are comfortable for swimming from late June through early September. Deeper lakes like Sebago and Moosehead stay cold well into July. Shallower lakes warm up faster. If you run cold, target Long Lake, China Lake, or Great Pond.
Algae blooms: Check the Maine DEP lake water quality reports before visiting, especially in late summer. Blue-green algae blooms occasionally occur and can be harmful to people and dogs. If the water looks like spilled green paint, do not go in.
Leave no trace: Pack out everything you bring. Maine’s clean lakes stay clean because people respect them. This includes food scraps, cigarette butts, and yes, the packaging from your sunscreen.
What is the cleanest lake in Maine?
Sebago Lake is the gold standard. It serves as Portland's drinking water supply without filtration, which requires extraordinary water clarity. Thompson Lake, Branch Lake, and Kezar Lake also consistently rank among the clearest in the state.
What is the warmest lake in Maine for swimming?
Shallower lakes warm up fastest. Long Lake in Naples, China Lake, and Great Pond in Belgrade are typically among the warmest by early July. Deeper lakes like Sebago and Moosehead stay cold much longer. For the warmest swim in the state, target shallow lakes in southern or central Maine.
Are there free swimming lakes in Maine?
Yes, many. Town beaches at Long Lake (Naples), Branch Lake (Ellsworth), Great Pond (Belgrade), Kezar Lake (Lovell), China Lake, Clearwater Lake, and Megunticook Lake (Barrett Cove) are all free. State park beaches charge $8 per adult.
When does the water warm up enough for swimming in Maine?
Most Maine lakes become comfortable for swimming by late June. Shallower lakes may be swimmable by early June. Deeper lakes like Sebago and Moosehead can feel cold into July. Peak water temperatures hit in late July and August.
Are Maine lakes safe to swim in?
Maine's lakes are generally very clean and safe. The main concern is occasional blue-green algae blooms in late summer, which can be toxic. Check the Maine DEP's lake monitoring page before visiting. Avoid swimming in water that looks unusually green or has surface scum.