Austria – Carinthian lakes
Carinthia's lakes warm up to well over 20 °C at the surface in summer, but below a sharp thermocline the water stays cold and dark, so most dives combine a sunny, plant-filled shallow zone with a cold wall below. The Weissensee, at about 930 m and protected as a nature park, is the region's diving highlight: clear water, sunken forests, steep walls up to 70 m and more, almost no motorboats, and two bases – Yachtdiver in Techendorf and Diving Weissensee on the east shore. In winter it freezes into Europe's largest natural ice surface and becomes a classic ice-diving destination with organised weekends. The Wörthersee offers deep walls and wartime relics below its warm surface layer, the Millstätter See – Carinthia's deepest lake at 141 m – has dramatic walls such as the Liafels, and the Klopeiner See requires a municipal dive permit. Smaller lakes such as the Längsee and the Freibach reservoir round out the picture.
Facts
- Water temperature and thermocline: In summer the surface layer of the big Carinthian lakes is warm: the official lake-temperature service shows readings of roughly 21–26 °C for the Wörthersee and Millstätter See, and the Weissensee reaches about 25 °C. The warm layer is shallow – on the Wörthersee about 8 m – and below the thermocline the water is dark and cold; historical Wörthersee measurements found about 4.1–4.3 °C from 50 to 80 m, and divers describe a 4 °C zone in the Klopeiner See. Use a drysuit or thick wetsuit for deep dives even in August. (check current terms)
- Altitude diving (Weissensee ~930 m): The Weissensee lies at about 930 m, 11.6 km long and up to 99 m deep. Dive computers switch from sea-level to altitude settings at a few hundred metres (e.g. Suunto: 0–300 m standard, 300–1,500 m altitude mode), which noticeably shortens no-stop limits; Suunto also recommends at least three hours of acclimatisation after arriving at altitude. Set the altitude mode before the first dive and plan with altitude tables. (check current terms)
- Ice diving on the Weissensee: Ice diving is offered only through the bases. Diving Weissensee (Stockenboi) runs all-inclusive weekends in late January and February (2027: five weekends, from €419 per diver; €599 including the ice-diving course; at least 10 divers), with ropes, hole cutting and closing done by the base. Its requirements: ice-diving certification, minimum age 18, valid dive medical, cold-water equipment with two independent regulators, drysuit, a buoyant, bright guide line rated above 2,000 N, a separate ~1.5 m buddy line, maximum line length 30 m in the water, a safety-diver line at least 10 m longer, and line ends fixed to a solid anchor. Yachtdiver (Techendorf) runs ice-diving days from six participants. The ice is typically around 30 cm thick. (check current terms)
- Boating rules on the Weissensee: Carinthia's lake-navigation law bans motorised vessels on the lakes listed in its annex, with lake-specific exceptions. On the Weissensee combustion engines are allowed only for licensed commercial operators (at most three vessels), professional fishing and certain transport; rental boats with combustion engines are banned, rental electric boats are limited to 500 W, and the quota for private electric boats of 4.4 kW or more is zero. Both dive bases use electric boats. (check current terms)
- Lake ownership and shore access: The beds of the Wörthersee, Millstätter See, Ossiacher See and Weissensee belong to the Austrian Federal Forests (ÖBf), but the shores are largely private – around 80% on the Wörthersee – so divers enter at lidos, lay-bys and base premises. On the Weissensee many sites lie in the nature-park protection zone and on private forest roads, reachable only by boat or the bases' shuttle; Yachtdiver holds official dive buoys granted by ÖBf. The Faaker See and its island are privately owned (freely accessible); no verified dive site there is listed here. (check current terms)
- Klopeiner See dive permit: Diving in the Klopeiner See needs a private-law permit from St. Kanzian municipality, issued by Dive Center Klopeiner See on showing a certification: €5 per day or €25 per calendar year (2024 prices). It is personal, must be carried on every dive and shown to municipal inspectors, and does not allow commercial training. Night dives only at Bad Süd between 18:00 and midnight, with a lamp fixed to the jetty. Base fee (€10/day) and lido entry are extra. (check current terms)
- Base fees and parking on the Weissensee: Diving Weissensee charges a daily base fee that includes beach entry for divers, €25 per guided dive and €8 per boat dive (full list in its price PDF; cash only). Yachtdiver's boat trip costs €109 per person, including two guided boat dives, two 10-litre fills, weights and the electric-catamaran ride (minimum 3, maximum 9 divers). Note that the east and west ends of the lake are not linked by a shore road. (check current terms)
- Wartime relics: Relics from the Second World War lie in the Ossiacher See and in parts of the Wörthersee (e.g. Teixlbucht). They are not souvenirs: recovering them is strictly prohibited, and they should not be touched. (check current terms)
- Emergency and chamber: Ambulance: 144. The hyperbaric chamber used for Carinthian lake dives is at the Medical University of Graz (Clinical Department of Thoracic and Hyperbaric Surgery, Auenbruggerplatz 29, Graz). The Weissensee bases keep oxygen kits on site and on their boats. (check current terms)
Season
- Best months: May, Jun, Jul, Aug, Sep, Oct
- Acceptable: Apr, Nov
- Poor: Dec, Jan, Feb, Mar
- Water temperature: 4–27 °C
The Carinthian lakes (Wörthersee, Millstätter See etc.) warm to 20–27 C in summer with good visibility; spring and autumn water is clearer. Ice diving is possible in winter. Sources differ on summer temperatures (Millstätter See 20–27 C).
Dive sites (24)
Klopeiner See & Lower Carinthia
- Freibacher Stausee – 0–20 m, beginner
- Klopeiner See – Strandbad Süd – 0–48 m, beginner
- Längsee – Strandbad – 0–22 m, beginner
Millstätter See
- Millstätter See – Döbriach (Strandbad Tschinder) – 0–13 m, beginner
- Millstätter See – Liafels – 0–45 m, advanced
- Millstätter See – Millstatt east (Heroldeck) – beginner
- Millstätter See – Seeboden (Strandbad Ertl) – 0–20 m, beginner
Ossiacher See
- Ossiacher See – Gerlitzenbad (Sattendorf) – beginner
Weissensee
- Weissensee Ost – Grillplatz – 0–30 m, beginner
- Weissensee Ost – Große Steinwand – 0–30 m, intermediate
- Weissensee Ost – House reef Kutsche & Madonna – 0–30 m, beginner
- Weissensee Ost – Kleine Steilwand – 0–30 m, beginner
- Weissensee Ost – Mikado – 0–30 m, beginner
- Weissensee – Elda wreck – 0–10 m, beginner
- Weissensee – Erker's Bay – 4–40 m, beginner
- Weissensee – Laka Wall – 0–30 m, intermediate
- Weissensee – Mopla (Techendorf house bay) – 0–10 m, beginner
- Weissensee – Rock Ronacher – 0–40 m, intermediate
- Weissensee – Steilwand North – 0–72 m, advanced
- Weissensee – Tschöllankofel – 0–55 m, advanced
Wörthersee
- Wörthersee – Reifnitz (Parkplatz 2) – intermediate
- Wörthersee – Sekirn Steilwand – 0–30 m, advanced
- Wörthersee – Strandbad Bad Saag – beginner
- Wörthersee – Teixlbucht / Messnerspitz – beginner
Operators (4)
- Yachtdiver / Taxiboot Weissensee – dive centre, Techendorf 46, 9762 Weissensee (Chillout Beach, Techendorf Süd, ~150 m past Strandbad Knaller)
- Diving Weissensee – dive centre, Strandbad Stockenboi, Mösel 11, 9714 Stockenboi (Weissensee east shore)
- Dive Center Klopeiner See – dive centre, Südpromenade 66, Strandbad Süd, 9122 St. Kanzian am Klopeiner See
- Tauchshop Klagenfurt – shop, Feldkirchner Strasse 117, 9020 Klagenfurt am Wörthersee
Routes (2)
Lake permits, base rules, ice-diving terms, fees and access to private shores change; check current terms with the local base or municipality before you dive. Several sites are deep, cold walls well beyond recreational limits, and the Weissensee lies at altitude – plan gas, thermal protection and decompression accordingly. Positions are for orientation only; many are approximate.