FAQs · Destination Guide
Cold-water wrecks, jewel-anemone walls and grey seals beyond Land's End
Frequently Asked Questions
Quick answers sourced from research and local operating patterns.
Plan a dedicated dive week between May and September. That window best matches local charter availability, longer daylight and the comparatively milder part of the Atlantic season. May and June can feel quieter, while July and August bring warmer conditions but stronger accommodation and transport demand. September often retains a summer-like feel. No month guarantees a flat sea: tides, wind and swell can still move the boat from a requested wreck to a sheltered reef or cancel a day. April and October require direct operator confirmation rather than assumption, and winter is not a dependable recreational charter season.
The local operation markets multi-day packages to qualified and experienced groups, so Advanced Open Water or equivalent with recent cold-water boat diving is the practical baseline. Some wrecks begin near 10 m, but the most interesting sections may descend beyond 30 m, with tidal streams, shot lines and Atlantic swell adding task load. A diver who has only calm tropical experience should complete UK cold-water and delayed surface marker buoy practice first. Wreck penetration, decompression or HMS Colossus access requires matching training, equipment and legal permission rather than enthusiasm alone.
Start with the boat, not the hotel. IOS Dive Charters operates Morvoren from St Martin's and advertises five-day packages for pre-formed groups of up to 10 qualified, experienced divers. Confirm dates, group competence, cylinders, fills, weights, protected-wreck plans and pickup quay before committing accommodation. Then decide whether St Martin's convenience or St Mary's broader services fit the group. The Scillonian III is often easier for bulky kit than a small aircraft, but every carrier's current baggage rules must be checked. Add a mainland buffer because delayed arrival could cost a scarce charter day.
Yes. HMS Colossus is a designated Protected Wreck Site under the Protection of Wrecks Act, and Historic England states that only licensed divers may visit it. Ask the local charter well in advance whether your group can be included under an appropriate visitor licence and whether the revitalized trail is planned. The site has two circular routes with numbered stations, but markers do not make it an ordinary open-access wreck. Follow the waterproof guide, avoid touching or recovering material, do not pull on trail lines and watch for exposed copper fastenings. A normal scuba certification alone is not permission.
The structured St Martin's seal-snorkel operator publishes trips from April through September, generally using a short RIB transfer to the Eastern Isles. The package includes a thick wetsuit, mask and snorkel, but participants must be comfortable swimming in open Atlantic water. Seals live around Scilly year-round, while pups begin appearing from late August and breeding activity continues into winter. Presence does not guarantee interaction. Stay calm, never chase, touch, follow or feed a seal, and keep away from hauled-out animals. The operator can cancel when sea or weather conditions are unsuitable.
Porthcressa on St Mary's, Great Bay and Lawrence Bay on St Martin's, and selected Tresco beaches are practical starting points when their side of the island is sheltered. The correct beach changes with wind direction, tide and boat traffic, so ask locally on the day rather than following a fixed ranking. Expect kelp, sand, granite and temperate invertebrates rather than coral. Wear suitable thermal protection, carry a bright tow float, stay close to shore and avoid harbor approaches. The Bar between St Agnes and Gugh is tide-limited and should not be treated as an all-tide casual swim route.
Scilly can be rewarding for a self-contained, conservative freedive team, but the reviewed sources do not establish a permanent deep line, dedicated freedive center or recurring competition. Plan for scenic bay sessions at places such as Porthcressa or Lawrence Bay, with deeper line work only after local permission and marine-traffic advice. June to September offers the best mix of warmer water and visitor support. Every session needs a trained buddy using direct one-up, one-down airway supervision, a visible float, thermal protection and a shore plan. Never freedive alone or turn a guided seal encounter into apnea training.
No responsible source can give a reliable trip-specific cancellation percentage. What is clear is that low cloud and fog can affect flights, strong wind can affect every mode, rough seas can interrupt the ferry and small boats, and low water can alter Scillonian III timings. Dive sites also depend on tide and exposure, so a transport day can run while an outer wreck is unsuitable. Protect the trip with flexible mainland connections, travel insurance and an on-island weather-day plan. Regard a skipper-led reef substitution as normal risk management, not evidence that the destination has failed to deliver.
Most groups should compare the Scillonian III with Skybus and helicopter rules before choosing speed over baggage flexibility. The ferry is often simpler for bulky dive bags, but equipment still needs robust labeling, waterproof protection and compliance with current carrier procedures. Small-aircraft capacity is constrained, so never assume a standard airline allowance applies to cylinders, weights or large camera cases. Confirm what Morvoren provides and leave unnecessary lead and tanks on the mainland. Carry certification records, medication, computer and regulator set in protected hand baggage where the carrier permits, and arrange the final harbor or airport transfer for the group's full kit volume.
A non-diver can build a full week around Tresco Abbey Garden and Valhalla, St Mary's Garrison and Peninnis walks, the low-tide crossing from St Agnes to Gugh, St Martin's beaches and produce stops, Bryher's contrasting coasts, and responsible wildlife boats toward Annet or the Western Rocks. April to July is strongest for breeding-seabird safaris, while July and August support specialist pelagics. The practical rule is to reserve one anchor activity and keep one same-island fallback. Inter-island boats and wildlife landings can change with weather, tide and conservation access, so rigid hour-by-hour plans are fragile.
The hospital and principal urgent medical services are on St Mary's, while visitors on the other inhabited islands may need a boat transfer. No local recompression chamber was identified in the reviewed official medical sources. For a diving emergency at sea, call Coastguard on VHF Channel 16 or 999, give 100 percent oxygen if trained and equipped, and then call the National Diving Accident Helpline on +44 7831 151523. Specialist mainland care, including DDRC Healthcare in Plymouth when directed, may require coordinated evacuation. Carry explicit diving and medical-evacuation insurance and preserve conservative gas and decompression margins.
The reviewed official visitor and conservation sources did not identify an islandwide tourism levy or a general paid marine-park dive tag. Visitors still pay normal transport, accommodation, activity and attraction charges. Marine protection is enforced through designations, fisheries rules, wildlife-access controls and responsible behavior rather than one universal tag. HMS Colossus is the key permit exception: it is a Protected Wreck Site open only to licensed divers. Other designated wrecks may also have site-specific rules. Ask the charter about every protected site, leave shellfish and artifacts in place, and recheck official information in case charges or rules change after the research date.