Slovenia – Coast

Slovenia has under 50 km of coastline, all on the shallow, sandy Gulf of Trieste, so diving here is easy and close to shore rather than deep and dramatic. The centre of activity is Fiesa near Piran, where several dive centres share a house reef full of small wrecks and night-time seahorses, cuttlefish and octopus. Around the tip of Piran the Rt Madona underwater monument has the coast's best rocky reef, and Portorož bay (Bernardin) stays calm when the bora blows. Further north the Strunjan and Debeli rtič parks protect seagrass meadows and pen shells – parts are closed to scuba or need the park's consent. A few Second World War wrecks (a barge, a German landing craft, a seaplane) are dived by boat from Fiesa.

Facts

Slovenia vs Croatia: Croatian diving permits do not apply in Slovenia, and Slovenia has no paid diving licence; the national diving decree (buddy rule, dive flag/buoy, certificate and medical) applies instead. Several sites lie in nature parks with their own rules – see below. Check current rules.
Buddy rule: Slovenia's diving decree requires divers always to dive in pairs of at least two, whatever the type of dive; solo diving is allowed only in listed special cases (e.g. rescue).
Marking the dive site: The dive area or entry point must be marked (dive leader's responsibility) with a white-blue 'A' flag, a red flag with white diagonal, or an orange/red ball of at least 30 cm on a float; at night the float needs a yellow or white light visible from 300 m. A diver's buoy is required equipment, and at least one diver per pair must carry a dive watch/computer and compass.
Certificate and medical: Under the 2003 decree on diving criteria a diver must hold a certificate of competence, and scuba divers need a medical certificate of fitness to dive. A dive plan filed with the civil-protection authority is required only for technical dives, not for recreational scuba dives.
Strunjan Nature Reserve: Scuba diving is prohibited in the central part of Strunjan Nature Reserve (the cliff coast between Moon Bay/Sv. Križ bay and Rtič Ronek) except for nature-conservation purposes; this zone also bans motor boats and anchoring. The reserve is a 200 m sea belt along the Strunjan cliff marked with yellow buoys, and collecting organisms and fishing (except hand-line) are banned throughout.
Debeli rtič Landscape Park: In protection zone 1 of Debeli rtič Landscape Park (Ankaran) scuba diving is allowed only by arrangement with the park manager (Municipality of Ankaran); park-wide, anchoring within 200 m of the coast and jet skis are banned and boats are limited to 7 knots.
Rt Madona natural monument (Piran): The underwater natural monument around Cape Madona (about 13 ha, a strip roughly 1 km long marked by four yellow buoys) bans motor boats, anchoring, spearfishing, collecting organisms for non-scientific purposes and pollution. No diving ban was found; dive boats drop divers outside the zone.
Sečovlje Salina Landscape Park: In the first protection zone of Sečovlje Salina Landscape Park (Fontanigge, Piketo canal and the Dragonja river) navigation and anchoring by any vessel are banned; fishing, noise and pollution are banned park-wide. No dive sites were found in the park.
Underwater cultural heritage: Slovenia ratified the UNESCO 2001 Convention on the Protection of the Underwater Cultural Heritage in 2008 and built its rules into national heritage law. The remains of the liner Rex between Izola and Koper are entered in the Slovenian Register of Cultural Heritage under no. 21615 – do not touch or remove anything from wrecks.
Conditions: Water temperature is about 24–26 °C in summer and 8–10 °C in winter. The bora stirs up sediment and spoils visibility on the north-facing coast (Fiesa, Strunjan, Piran Punta); Portorož bay (Bernardin) is sheltered and often clearer then. The bottom is mostly sand and mud, so visibility is modest – around 5 m is considered good at Fiesa.
Emergency number: 112 – ambulance, fire brigade, mountain and cave rescue and other rescue services; 113 – police.
Recompression chamber: No official source was found confirming a 24/7 recompression chamber in Slovenia. A Slovenian diver with decompression sickness was treated in the hyperbaric chamber of the hospital in Rijeka, Croatia (2022 news report). Confirm current options with 112 / DAN before diving.

Season

Best months: Jun, Jul, Aug, Sep
Acceptable: May, Oct
Poor: Nov, Dec, Jan, Feb, Mar, Apr
Water temperature: 7–26 °C

PADI says year-round diving (about 10 C winter, 26 C summer), but a university study puts the season at May to October (17–24 C), with sea temperatures falling to 7 C in February. Shallow reefs; visibility drops after rain.

Dive sites (14)

Piran, Fiesa & Portorož

Bernardin – 0–12 m, beginner
Fiesa Reef – 0–15 m, beginner
Gilda (WWI steamer) – 21–28 m, advanced
Kec (MFP F-956) – 18–24 m, advanced
Maona Rossa – 16–23 m, intermediate
Pacug – beginner
Piran Punta – 3–22 m, beginner
Piran under the church – 4–16 m, beginner
Seaplane wreck (Bernardin) – 12–14 m, beginner

Izola & Strunjan

Cape Kane below Belvedere (Izola) – 0–10 m, beginner
Cape Ronek, Strunjan cliff (TILOS / no diving) – 0–15 m, intermediate
Rex wreck remains – intermediate
Strunjan – 0–14 m, beginner

Koper & Ankaran (Debeli rtič)

Debeli rtič – 0–10 m, beginner

Operators (4)

Nemo Divers – dive centre, Fiesa 57, Piran (Slovenia)
Piran Diving (Sharky dive centre, Fiesa) – dive centre, Hotel Fiesa, Fiesa 57, Piran (Slovenia)
Divestrong – dive centre, Hotel Barbara, Fiesa 68, Piran (Slovenia); shop at Marina Portorož
Oceandiving – dive centre, Soška ulica 8a, Koper (Slovenia)

Routes (3)

Positions marked approximate are for orientation only, never for navigation; wreck positions are not published. Parts of the coast are protected (Strunjan, Debeli rtič, Rt Madona, Sečovlje) – check current park rules, always mark your dive with a flag or buoy and watch boat traffic.