Swimming on the Isles of Scilly: Best Spots, Sea Temperatures and Safety
Clear water, white sand and sheltered bays make the Isles of Scilly a swimmer's dream. Here are the best spots, sea temperatures by month, seal snorkelling, swim events and the safety basics to know.
Something changed? Tell us
Swimming on the Isles of Scilly is hard to beat. White sand, shallow bays and sheltered channels between the islands give you clear water in many weathers. Islandeering rates the seas here among the cleanest in the UK. It is still the Atlantic, though, so it pays to know where and when to go.
This guide covers the best places to swim on each island and sea temperatures through the year. It also explains how to snorkel with grey seals, which swim events to enter, where to find the island pool and the safety basics you need. It works for first time visitors and regulars with a favourite bay alike.
Key Takeaways
- The best time to swim is July to September, when the sea averages around 16 to 17°C.
- Calm, family friendly bays include Porthcressa and Pelistry on St Mary's, Pentle Bay on Tresco and Great Bay on St Martin's.
- Swimming with seals trips leave St Martin's for the Eastern Isles, with wetsuits and snorkel kit included.
- Don't expect lifeguards. Check the tides, swim with a buddy and call 999 for the Coastguard in an emergency.
- Normandy Pool on St Mary's is the islands' only public pool and is open all year.
Why Swim on the Isles of Scilly?
The islands sit close together, so the water between them is more sheltered than the open coast. Islandeering points out that this makes swimming possible in many sea states. Isles of Scilly Travel adds that most beaches here suit families, with very little slope into the water.
Pick a sunny day at low tide and the shallows glow turquoise.
The trade off is temperature. Suitcase magazine notes that without the mainland to warm it, the water here feels colder than Cornwall's. Expect a bracing dip rather than a warm one, even in August. A wetsuit makes longer swims far more comfortable and buys you time to explore, especially outside July and August.
When Is the Best Time to Swim on Scilly?
The sea is warmest from July to September. Figures from Weather2Travel put the average at about 17°C in August and 16°C in July and September. It drops to around 10°C from January to April. Seasoned local swimmers go in all year, but most visitors will find late summer the most comfortable.
Isles of Scilly Sea Temperature by Month
| Month | Average sea temperature | What to expect |
|---|---|---|
| January to April | 10°C | Cold water swimmers only |
| May | 12°C | Wetsuit recommended |
| June | 14°C | Bracing but doable |
| July | 16°C | Good swimming |
| August | 17°C | Warmest month |
| September | 16°C | Good swimming, quieter beaches |
| October | 14°C | Wetsuit recommended |
| November | 12°C | Cold water swimmers only |
| December | 11°C | Cold water swimmers only |
September is worth a look. The sea is close to its August peak, and the beaches get quieter once the school holidays end.
Best Places to Swim on the Isles of Scilly
Every inhabited island has good spots, from easy beach dips to wilder swims off the rocks. These are some of the best. Check the tide before you go, as some spots change a lot between high and low water.
RecommendedIsland lifeIsles of Scilly Steamship Company: Skybus Troubles, Leadership Changes and What Comes Next9 min read · All islandsRead the story →St Mary's: Porthcressa, Pelistry and Peninnis
Porthcressa sits right next to Hugh Town. Islandeering says rocks shelter it on both sides, so the water is often calm. Cafés line the promenade for a hot drink afterwards. It is the easiest swim on the islands if you are staying in town or only here for the day.
Pelistry Bay, in the quieter north east, is shallow and sheltered. You can swim out to Toll's Island at low tide, and Carn Vean Tearooms is a short walk away. For something wilder, Peninnis Head has ledges you can drop in from, but it often picks up swell from the open Atlantic.
St Martin's: Great Bay and Lawrence's Bay
Great Bay on the north coast is remote and unspoilt. Isles of Scilly Travel calls it a haven for families thanks to its calm water. At low tide you can cross a pebbly bar to White Island and swim in the shelter of Porth Morran. Lawrence's Bay on the south coast offers clear, shallow water over seagrass.
Lawrence's Bay is at its best near high tide, so plan around the tide table.
Tresco: Pentle Bay and Appletree Bay
Pentle Bay is a long, gentle arc of white sand. Isles of Scilly Travel says you can wade out a long way at low tide, which makes it ideal for children and first time swimmers. Appletree Bay and Ravensporth are good alternatives, and Islandeering suggests pizza at the Ruin Beach Café afterwards.
Bryher: Rushy Bay and Shipman Head
Rushy Bay, at the southern tip, looks across to Samson. Islandeering rates it for shallow water, low currents and good snorkelling close to shore. At the other end of the island, the gully at Shipman Head is a deep, dramatic swim. Only try it at low slack tide when the swell is down.
St Agnes and Gugh: The Bar
The Bar is a sand spit that joins St Agnes to Gugh at low tide. It offers very sheltered swimming and snorkelling, and it is a short walk from the quay and the Turk's Head. Islandeering gives one firm rule here. Only swim when the Bar is uncovered, to avoid dangerous currents.
Samson: Bar Point
Bar Point on uninhabited Samson can only be reached by boat. The water is shallow and very clear, and it can feel like your own desert island. Islandeering suggests arriving early, before the summer boat trips bring more visitors. return times on the Scilly Live board before you set off, so you are not left stranded.
Swimming With Seals on the Isles of Scilly
snorkelling alongside Atlantic grey seals. Trips leave Higher Town on St Martin's and head by RIB to the uninhabited Eastern Isles. According to Isles of Scilly Travel, the seals lead each encounter, so no two trips are the same. Guides look after both nervous and confident swimmers.
What a Seal Snorkelling Trip Involves
- Where: Higher Town, St Martin's
- When: Daily at 09.15 and 12.45
- How long: About 2 hours 30 minutes
- Price: £85 per person (2026)
- Group size: Up to 10 people
- Kit: Wetsuit, mask and snorkel provided, plus a hot drink and snack afterwards
RecommendedSightseeingPlaces to visit on the Isles of Scilly8 min read · All islandsRead the guide →Getting there from St Mary's is simple. Seal Snorkelling Adventures says a boat leaves St Mary's at 8.45am every day for the morning session. For afternoon trips, ask the St Mary's Boatmen's Association or boat times on the Scilly Live board. Book ahead in summer, as groups fill quickly.
How to Behave Around Seals
These are wild animals, and the seals decide how close they come. The Isles of Scilly Wildlife Trust asks snorkellers to keep a good distance and never try to touch them. The Trust says the breeding season runs from August to December, so take extra care in autumn.
- Let the seals come to you and never chase them
- Don't touch a seal, even if it nibbles your fins
- Keep well away from seals resting on rocks
- Move away if a seal shows any sign of disturbance
Swim Events and Challenges on Scilly
The Scilly Swim Challenge
Run by SwimQuest, the Scilly Swim Challenge is a 15km island hopping swim. It is split into five swims with short walks or breaks between them. You can do it in one long day or spread it over two. It is a challenge, not a race, and safety cover comes from a team of open water experts.
It is popular. Voice Newspapers reported nearly 400 swimmers in 2025, backed by more than 60 helpers and kayakers. The organisers even hand out a prize for the friendliest swimmer rather than the fastest. Routes can change with the weather, but every swimmer still gets in the water.
- Two day event: 9 and 10 September 2027, £385.75 general entry
- One day event: 12 September 2027, £304.50 general entry
- Charity places: Half price entry with Level Water, plus a fundraising target
Scilly Swimrun Events
Swimrun races mix coastal trail running with sea swims between islands. In 2026 the series included the St Agnes Swimrun in July and the St Mary's Swimrun in August. A wetsuit, whistle and soft flask are compulsory. Organisers quote water temperatures of about 14 to 16°C in July.
Guided Swims Between the Islands
If you want to swim between islands without entering an event, go with a guide. Islandeering lists guided routes such as Tresco to Bryher and Samson at 2.5km, and Tean to St Martin's at just 190 metres. The longest runs 3km from Higher Town on St Martin's to Bar Point on St Mary's.
Swimming Pools on the Isles of Scilly
Normandy Pool, St Mary's
When the sea is too rough or too cold, Normandy Pool is the backup. The Council of the Isles of Scilly runs this 14m indoor pool on the road between Porth Hellick and Pelistry. It is open all year to visitors and residents, with public sessions, family swims and lessons.
- Adult swim: £8 for non members, £6 for Active Scilly members
- Child or concession: £5.90 for non members, £4.30 for members
- Bookings: Advised, as sessions fill up. Call 01720 424400
- Children: Under 8s must be supervised by someone aged 16 or over
RecommendedHistoryIsles of Scilly Ghost Stories: Legends, History and Where to Find Them12 min read · All islandsRead the story →Prices apply from 1 April 2026, according to the council's pool page.
Hotels With Swimming Pools
A few places to stay have their own pools. Listings on Visit Isles of Scilly show an indoor pool at the Bell Rock Hotel on St Mary's, open from March to October. On Tresco, the Island Spa has an indoor pool too. Always check with the venue before booking.
How to Swim Safely on the Isles of Scilly
Don't expect lifeguards. Beach listings on Sandee show no lifeguard cover at popular spots such as Pelistry Bay and Gugh. You are responsible for your own safety. The tides are big too. Visit My Harbour gives a spring tide range of about 5 metres at St Mary's.
That much water moving in and out creates strong currents over sandbars and through channels.
- Check the tide times before every swim
- Swim with a buddy or tell someone your plan
- Wear a bright swim cap and use a tow float in deeper water
- Get in slowly to avoid cold water shock
- Watch for boats, especially near quays and moorings
- Stay out of the water when the sea is rough
If you get into trouble, the RNLI advises you to Float to Live. Lean back, spread your arms and legs and keep your breathing steady until the cold water shock passes. If you see someone else in difficulty, call 999 or 112 and ask for the Coastguard. Don't go in after them yourself.
What to Pack for a Swim on Scilly
Space on the boats is limited, so pack light but warm. Islandeering recommends these essentials:
- A wetsuit for longer swims and cooler months
- Neoprene gloves and socks for extra warmth
- A changing robe or warm layers for afterwards
- A waterproof bag for your phone and keys
- Reef safe sun cream
Local Swimming Groups
Island swimmers are a welcoming bunch, and joining them is the best way to learn the local spots. Islandeering points to the Scilly Sea Swimmers group on Facebook and Wild and Scilly Mermaids on Instagram. For guided swims and local knowledge, it recommends Adventure Scilly.
Swimming on the Isles of Scilly: Quick Answers
Is the sea warm enough to swim on Scilly?
Yes, in summer. The sea averages about 16 to 17°C from July to September. It is fresh rather than warm, so many swimmers wear a wetsuit for longer dips.
Which Scilly beach is best for children?
Pentle Bay on Tresco, Porthcressa on St Mary's and Great Bay on St Martin's are all good choices. They are sheltered, and the sand slopes gently into the sea.
Can you swim between the islands?
Yes, but go with a guide or join an organised event such as the Scilly Swim Challenge. Tides, currents and boat traffic make unguided crossings risky.
Are there lifeguards on Scilly beaches?
Don't count on it. Plan as if there are none, check the tides and call 999 for the Coastguard in an emergency.
Is there a swimming pool on the Isles of Scilly?
Yes. Normandy Pool on St Mary's is a 14m indoor public pool, open all year. Book on 01720 424400.
