Zeeland · Netherlands · Artificial reef · Reef
Den Osse
An artificial reef on the tideless side of Zeeland
Photo: Bart Braun · Public domain
Kerkweg at Den Osse is one of the best-known dive entries in Zeeland: from the jetty you drop straight onto oyster beds, a ribbon of reef balls and other hard substrate that has grown over well. The bottom runs down to about 30 metres, but the life is concentrated in the shallows and most dives stay up there.
Also known as Kerkweg, Den Osse.
Where it is and how deep
51.7429° N, 3.8796° EPublished position for this site.
The dive
You enter from the jetty, which puts you straight onto the good ground rather than making you swim for it. The oyster beds, the reef balls and the rest of the hard substrate sit in the shallows, and the growth on them is what the dive is for: nudibranchs, pipefish, gobies, ghost shrimp, European lobster and North Sea crabs work the overgrown surfaces. The bottom goes on down to roughly 30 metres, but there is little reason to follow it, since the life thins out as you go.
The Grevelingen is closed off from the sea and its dive sites are not subject to tides, so the timing here is yours: this is a site you can work slowly over a small patch and come back to later the same day. Visibility logs between 3 and 6 metres across the year and is at its best in November, and the water runs from 5°C in midwinter to 20°C in high summer, which means a drysuit for most of the calendar.
Marine life and season
- Nudibranchs
- Macro critters
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Good | Good | Good | Prime | Prime | Prime | Good | Good | Good | Good | Good | Good |
Season follows Zeeland: Cuttlefish season runs Apr–Jun and is the year's highlight; winter is coldest at 4°C but gives the clearest water.
Know before you go
- The site runs to about 30 metres, well past the shallow ground the dive is aimed at; agree a maximum depth before entering rather than following the slope down.
Photos from Den Osse
Bert Kaufmann from Roermond, Netherlands · CC BY 2.0
Bert Kaufmann from Roermond, Netherlands · CC BY 2.0
Dive videos
Grevelingen, Den Osse, Nieuwe Kerkweg, duiken · Dirk Van den Bergh on YouTube
Questions divers ask
How deep is Den Osse?+
The site runs to about 30 metres, but most of the life sits in the shallows over the oyster beds and reef balls, so a typical dive here stays well above the bottom.
Is there current at Den Osse?+
It sits on the Grevelingen, which is closed off from the sea and not subject to tides, so there is no slack-water window to plan around, unlike the Oosterschelde entries a few kilometres away.
Sources
- Kerkweg, Den Osse — Scubago
Photo credits
- European lobster with long red-banded claws wedged into a rocky crevice underwater by Bart Braun, Public domain, via Wikimedia Commons
- Dark storm clouds gathering over the flat surface of the Grevelingenmeer by Bert Kaufmann from Roermond, Netherlands, CC BY 2.0, via Wikimedia Commons
- Evening light reflecting on the calm water of the Grevelingenmeer by Bert Kaufmann from Roermond, Netherlands, CC BY 2.0, via Wikimedia Commons
In The Logbook
- How far you can see underwaterOcean science · 12 min read
- Why is some sea green instead of blue?Ocean science · 8 min read
- Cold-water diving: is it worth the drysuit?Cold water · 8 min read
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