Dive sites in Denmark

The narrow strait at Middelfart creates a natural funnel for tidal currents, which concentrates fish and nutrients in a relatively small area. Harbour porpoises, Denmark's only native cetacean, gather here to feed on the abundant fish brought in by the currents. The area hosts one of the densest concentrations of harbour porpoises in European waters, with populations peaking during the summer months when fish are most abundant.

Currents at Middelfart can be very strong, sometimes exceeding two knots during peak tidal flow. Diving must be carefully planned around tide tables, with slack water periods offering the calmest conditions for less experienced divers. Many divers specifically choose to dive during moderate current periods for drift diving, entering upstream and letting the current carry them through the strait. A surface marker buoy is essential, and diving with a local guide familiar with the current patterns is strongly recommended.

While harbour porpoises are present in the area year-round and in large numbers during summer, underwater encounters during dives are not guaranteed. Porpoises are fast-moving and can be shy of divers. However, surface sightings are virtually guaranteed during summer months. Underwater encounters are most likely during drift dives when the current matches porpoise feeding behavior. Snorkeling in shallow areas can also provide excellent encounters as porpoises sometimes feed very close to shore.

The Little Belt is one of the narrowest straits in Denmark and the tidal currents can exceed three knots at peak flow. Diving is only safe during slack tide windows, which last roughly 30 to 45 minutes. Local dive centres publish daily slack tide predictions and most guided dives are timed precisely to these windows. You must carry a surface marker buoy and many divers use a reef hook for the deeper sections. An advanced open water certification and experience with current diving are strongly recommended.

The Little Belt hosts one of the densest populations of harbour porpoises in the world, with an estimated 3,000 animals using the strait. While they are occasionally seen underwater, sightings are more reliable from the surface during intervals. The best porpoise months are June through August when mothers bring calves into the shallow, fish-rich waters. The Middelfart area has a dedicated porpoise research station and several operators offer combined snorkelling and porpoise observation trips.