Safety · Destination Guide
Cold-water wrecks, alpine walls and clear shallows beneath the French Alps
The defining risks are cold depth water, low light, variable visibility, silt, steep bathymetry, wreck overheads, boat traffic and post-dive elevation changes. Organized diving in France operates within a formal supervision and rescue framework, and visiting divers should use established local providers rather than improvising access. Conservation centers on protecting drinking-water quality, weed beds, historic remains and ecological monitoring rather than a tropical marine-park tag.
Plan exposure protection and gas around the deepest point. Le France can be around 4°C to 6°C in darkness even when Lake Annecy's surface is summer-warm. Cold increases gas consumption, task loading and regulator stress. Use a conservative turn pressure and a cold-water rated system.
Carry a compass, maintain close team spacing and avoid the bottom. Suspend the dive if visibility deteriorates beyond the team's practiced limits. A primary and backup light are appropriate for deep walls and wreck exteriors.
Do not penetrate a wreck without formal overhead training, a continuous guideline, redundancy and the operator's approval. Walls at Le Fenalet, Roc de Chere and Duingt continue beyond recreational limits, so establish maximum depth before descent.
Use the locally required flag or surface marker, stay outside navigation lanes and arrange a shore watcher where appropriate. Alpine roads can climb after the dive; agree on post-dive routes and waiting periods with the dive professional rather than relying on a generic sea-level rule.
For a serious diving symptom, give emergency oxygen when trained and available, call 112 or 15, state that it is a diving incident and follow emergency-service direction. Do not self-drive a symptomatic diver to a chamber. The regional hyperbaric reference is the Centre de Medecine Hyperbare at Hopital Edouard Herriot in Lyon, but dispatch and treatment choice should be coordinated by medical services. DAN Europe provides 24-hour diving-emergency assistance at +39 06 4211 5685. Local hospitals in Annecy, Chambery/Aix and Thonon/Evian can provide initial assessment and stabilization. Keep dive profiles, computer data, gases and symptom timing available for responders.
Warm surface, cold depth
A summer surface near 25°C can conceal an abrupt thermocline and very cold deeper layer. Dress and plan for maximum depth, not the beach reading.
Silt and low light
Poor trim or a misplaced fin kick can remove visual references. Maintain team contact, use a compass and carry redundant lights on deep or dark profiles.
Wreck overheads
Le France and other wrecks may tempt entry, but penetration requires dedicated training, a continuous guideline, suitable gas, redundancy and operator authorization.
Wind and boat traffic
Afternoon chop and summer craft can compromise a shore exit or freedive safety zone. Use local flags, surface support and operator-selected entries.
Lake Annecy management, CISALB and CIPEL all frame these waters as shared ecological resources. Low-impact technique is therefore a core destination skill.
Do Not Do This
Avoid entering when warm surface, cold depth. Confirm local briefings before committing.
| Contact | Role | Phone | Availability |
|---|---|---|---|
| European emergency number | Police, fire or medical emergency routing | 112 | 24 hours daily; free |
| SAMU | Urgent medical assessment and dispatch in France | 15 | 24 hours daily; free |
| Sapeurs-pompiers | Rescue and fire service | 18 | 24 hours daily; free |
| DAN Europe Emergency Hotline | Diving medicine and emergency assistance | +39 06 4211 5685 | 24 hours daily |
| Lyon Poison Control Center | Toxicology advice including suspected cyanobacteria exposure | +33 4 72 11 69 11 | 24 hours daily |