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The Den Oever lock at the western end of the Afsluitdijk will be closed completely to shipping twice for several months: from 1 October 2027 to 1 June 2028 and from 1 October 2028 to 1 June 2029. The Dutch waterways authority Rijkswaterstaat announced this on 26 October 2026 (as of October 2026). Everyone travelling between the IJsselmeer and Wadden Sea are out sailing, whether on their own boat, on a charter yacht or as a guest on board.
The essentials at a glance
- The Stevin lock in Den Oever is closed to all vessels from 1 October 2027 to 1 June 2028 and from 1 October 2028 to 1 June 2029.
- In the summer in between, from 1 June to 1 October 2028, passage is open again. The 2027 season remains unaffected until the end of September.
- The reason is the replacement of the two swing bridges on the A7 motorway that cross the lock, together with the lock's control system.
- During the closure, only the second passage in the Afsluitdijk remains: the Lorentz locks at Kornwerderzand at the eastern end of the dam.
- The width and headroom of the bridges are to remain the same after reconstruction.
When is the Den Oever lock closed?
The Den Oever lock is closed in two phases, each from early October to early June. In between lies an open summer.
| Period | Den Oever passage | Works |
|---|---|---|
| until 30 September 2027 | open | Preparation |
| 1 October 2027 to 1 June 2028 | closed | Replacement of the southern bridge |
| 1 June 2028 to 1 October 2028 | open | Break for navigation |
| 1 October 2028 to 1 June 2029 | closed | closed |
Replacement of the northern bridge
The closure periods fall in autumn, winter and spring, i.e. in the months with little boat traffic. In summer, the Stevin lock sees an average of around 130 vessels a day, of which about 115 are pleasure craft. In winter it's an average of three, and exclusively commercial vessels.
For sailors this means: anyone planning for the high season will notice little of the construction work in Den Oever. Things get tight in the shoulder seasons, i.e. in April, May and from October onwards.
What exactly is being built in Den Oever?
A foretaste of the consequences: in July 2025, water damage caused a switchboard beneath the northern bridge to fail; the passage was closed for several days. Rijkswaterstaat diverted shipping via Kornwerderzand at the time.
Which trips does the closure affect?
Every trip that is due to pass between the IJsselmeer and the Wadden Sea, or vice versa, during the closure periods via the western side of the Afsluitdijk is affected. The 32-kilometre dam has only two locks: the Stevin lock at Den Oever and the Lorentz locks at Kornwerderzand.
Den Oever is the short route for anyone heading from the IJsselmeer towards Texel, Den Helder or the western part of the Wadden Sea. Typical situations where you will need to replan:
- Deliveries to winter storage from October 2027 and from October 2028.
- Spring trips in April and May 2028 and 2029, for example from harbours on the IJsselmeer to the western Wadden Islands.
- Mile-building and sail-training trips in the off-season that involve switching between the inland sea and tidal waters.
- Return passages from the North Sea to the IJsselmeer that previously ran via Den Helder and Den Oever.
If you are sailing as a guest on board a yacht, the main change for you will be the route. The detour via the Lorentz locks may mean a different day's destination or an additional day at sea.
How do you get from the IJsselmeer to the Wadden Sea during the closure?
The only link through the dam will then be the Lorentz locks at Kornwerderzand. They are at the eastern end of the Afsluitdijk, not far from Harlingen.
Kornwerderzand is already the busier lock today. In summer an average of around 260 vessels pass through per day, of which about 225 are leisure craft. In winter the average is 16, including 4 leisure craft.
Important for planning:
- On the Wadden Sea side, the tide and fairways determine the times. Anyone wanting to head west from Kornwerderzand should plan the passage around high and low water, not just the lock times alone.
- From the IJsselmeer at Kornwerderzand to Texel, the route through the Wadden Sea is longer than the direct route via Den Oever. Allow a buffer day for deliveries.
- Rijkswaterstaat is also working at Kornwerderzand over the coming years, including on the drainage locks. Later the bridges there are also to be renewed. The projects will run consecutively so that road and ship traffic is not disrupted too severely. Short closures are nevertheless possible.
What changes for the 2027 season?
Nothing changes at Den Oever for the 2027 season until the closure begins on 1 October. The lock operates normally throughout the summer.
Anyone wanting to bring a boat back from the Wadden Sea to the IJsselmeer in autumn 2027 should do so before the end of September or plan the passage via Kornwerderzand from the outset. The same applies in autumn 2028.
Where do you get authoritative information?
The authority responsible is Rijkswaterstaat, the Dutch waterways authority. The official announcement regarding the swing bridges at Den Oever sets out the closure periods. Whether a lock or bridge is open on a particular day is shown on vaarweginformatie.nl with the current notices to shipping. Check there shortly before each passage. The authority itself points out that planning on the Afsluitdijk may still change.
Frequently asked questions
Is the Den Oever lock open in summer 2027?
Yes. The first closure begins on 1 October 2027. Until then the passage is open as normal.
Can I pass through Den Oever in summer 2028?
Yes. From 1 June to 1 October 2028 the Stevin lock is open to shipping. After that follows the second closure until 1 June 2029.
Will the bridges at Den Oever become lower or narrower?
No. Width and clearance height remain the same according to the plans. Steel, drive and controls are being renewed.
Which lock do I use during the closure?
The Lorentz locks at Kornwerderzand at the eastern end of the Afsluitdijk. They will then be the only way through the dam.
Is road traffic also affected?
Yes, but to a limited extent. The Afsluitdijk remains open to cars, with at least one lane in each direction. Especially on Fridays, during rush hour and in summer, the journey takes longer. For individual works the A7 will be briefly closed.
Find sailing trips on IJsselmeer and Wadden Sea
Those planning now for 2027 and 2028 are best looking for sailing trips that move between IJsselmeer and Wadden Sea during the open months. On Törnfinder you'll find offers for Sailing on the IJsselmeer and further sailing trips for Sailing in the Netherlands. Read more about harbours in the region in the profile of Harlingen near Kornwerderzand and in the article about the harbours of Enkhuizen on the IJsselmeer.
