Fort Island IJmuiden – Guarding the water way to Amsterdam, the Netherlands

Coastal Fort IJmuiden Netherlands
A view of Fort Island IJmuiden in the Netherlands – Photo Landmarkscout 2022

Connecting the Port of Amsterdam to the North Sea, the Dutch Noordzeekanaal estuary is a very busy place. Day and night big cargo ships and tankers come and go, either to dock at one of the piers in IJmuiden or pass through to the Port of Amsterdam. The area here is constantly changing under the influence of economic growth, industrial innovation and human ingenuity. With bigger and better harbor facilities and longer docks and faster cranes for even larger ships.
Yet in the center of the buzzing estuary lies a small island that was pretty much left to it’s fate for five decades following World War Two. The island is known as Fortress Island IJmuiden.

UNESCO World heritage

This changed when UNESCO put Fort Island IJmuiden on it’s list of world heritage sites in 1996 along with the Defense Line of Amsterdam. Since then the restoration of the Fort started and from 2004 on the Fort can even be visited again. Nowadays it is one of the most popular sights in the IJmuiden area.

Fort at IJmuiden

Fort IJmuiden from above
Fort IJmuiden seen from above

When Fort at IJmuiden was built between 1881 and 1888, it wasn’t on an Island at all. It was in fact on the North shore of the main land guarding the sea lock towards Amsterdam. Being part of the Defense line on a forward key position, it was among the strongest and largest of a total of 43 forts and batteries. With 3 floor levels of which 2 subterranean, enough rooms and facilities to house a capacity of around 300 men, an underground tunnel system of 585 meters long, a coastal battery made of one meter thick cast iron equipped with five 24cm L30 canons facing the sea and a 360° rotating steel armored turret with two 15cm L30 canons, it posed a serious threat to any attacker.

Fort IJmuiden the Chapel
View from “The Chapel” with a look into the hallways of Fort at IJmuiden
Fort IJmuiden Battery
The Fort IJmuiden gun battery seen from above
Fort IJmuiden battery front
The five gun ports of the coastal battery of Fort IJmuiden
Inside battery Fort IJmuiden
The inside of the impressive cast iron coastal gun battery of Fort IJmuiden
Gun battery Fort IJmuiden
The inside of the cast iron coastal gun battery seen from the other side
Fort IJmuiden sea battery
An instruction table with firing corrections for the 24cm gun written on the inside of the cast iron
Fort IJmuiden turret
The original armored gun turret of Fort at IJmuiden approx. 1935 – Collection Netherlands Institute of Military History
Fort IJmuiden turret remains
The gun turret today with the German concrete alterations from WW2 at Fort IJmuiden
Inside the gun turret
A look up inside the remnants of the former rotating turret fitted with the 15cm guns of Fort IJmuiden
Sleutelgang Fort IJmuiden
Looking through the “Sleutelgang” or in English “Keyhole corridor “of Fort IJmuiden, the Netherlands


The Netherlands declared itself neutral during World War One (1914-1918). Fort at IJmuiden was put on full alert and a regiment of around 300 men were stationed here to react to a military threat. Fortunately the Netherlands managed to stay out of the war.

Fort IJmuiden WW1
A picture of the Fort IJmuiden Orchestra in 1914 during the mobilization for WW1 – Collection Netherlands Institute of Military History

Becoming an Island Fort

To allow for more and larger shipping a new channel was dug next to the old one at the North side in 1929. With this the Fort at IJmuiden was cut off from the main land and came to be situated on an Island. The aerial pictures underneath show the situation before (at around 1925) and after (at around 1940).

Aerial of Fort IJmuiden
Aerial picture of Fort at IJmuiden taken around 1920-1925 – Collection Netherlands Institute of Military History
Aerial photo Fort at IJmuiden
Aerial picture of Fort at IJmuiden taken around 1940 – Collection Netherlands Institute of Military History


With the rise to power of Adolf Hitler and his Nazi Party in Germany, the threat of another war in Europe was growing. And so the Netherlands mobilized it’s army from 1938. Fort at IJmuiden had become outdated, but it was again put on alert and a garrison was installed. Unfortunately this time the Netherlands did not manage to stay out of the war, despite declaring it’s neutrality as it had done before.

After Germany invaded the Netherlands the Fort was at first used as an ammunition storage. The 24cm canons together with the armored turret were dismantled and scrapped. But when the German High Command (OKH) ordered the construction of the Atlantic Wall against a possible Allied invasion, the island became part of the defensive line under the name of Widerstandsnest 73 (or short WN 73) of Festung IJmuiden. The Germans rearmed the fort with heavy guns, placed dragon teeth anti tank obstacles and added 26 bunkers to the island.

German additions in WW2

Not all the German additions are still present on the island today. Many of the bunkers were demolished when the Eastern part of the island was removed in 1967.
Underneath we have listed some of the remaining constructions that are still present today. These are all under the care of the WOVIJ foundation and most can be visited during public visiting days.

Höckerhindernisse – anti-tank obstacles

IJmuiden dragon teeth WW2
German “dragon teeth” anti tank obstacles of WW2 at Fort Island IJmuiden, Netherlands

On the Western side of the island, the Germans placed a line of anti-tank obstacles called “Höckerhindernisse” or Dragon Teeth to prevent tanks and (amphibious) vehicles from getting ashore.

Bunker Type M170-656 (South)

Bunker Type M170-656 SK
Bunker Type M170-656 (South) at Kernwerk IJmuiden, Netherlands

This bunker is a type M170-656 Gun emplacement which used to house a large 15cm gun. The bunker is coupled with a Type 656 personnel bunker at the back. Together with the remaining M170-656 North bunker (largely demolished) and M170-656 West bunker, these combination types are unique along the Atlantic Wall. The inside of the bunker is connected to the old fort through a tunnel.

Bunker Type 631 – Schartenstand für PAK

Bunker Type 631 IJmuiden
Bunker type 631 on Fort Island IJmuiden, Netherlands

This bunker is situated behind the dragon teeth facing the sea estuary. It housed a 4,7cm PAK anti-tank gun, a MG-stand and sleeping quarters for its crew. On top is a Tobruk that could also be fitted with a MG. The bunker was there to prevent a landing on the South-Western corner of the Island.
Outside of the bunker are some of the original trenches running past the dragon teeth. Watch the Landmarkscout Fort Island IJmuiden drone video where we fly over the island and you can see the trenches still clearly visible.

Bunker Type 671 SK Schartenstand der 9,4cm

Bunker type 671 SK IJmuiden
German Bunker type 671 SK Schartenstand on Fort Island IJmuiden, the Netherlands

This bunker is an adapted version of the Regelbau type 671 Schartenstand, which is why it is designated “SK” on the Baufortschrittskarte of “Kernwerk IJmuiden” (German construction plan). SK stands for “Sondern Konstruktion” meaning exceptional or special construction. The exceptional part of this bunker is that the personnel entrance is located on its left flank instead of at the back. Notice that the bunker still largely has its plastered camouflage pattern covering the concrete.

The bunker was placed here to defend the island towards the mainland on the South-East corner. It was equipped with a captured English Vickers 3.7 inch (9,4cm) gun.

Bunker type 671 gun base
The gun base inside bunker type 671 SK

Bunker type 636 SK Leitstand

Type 636 SK IJmuiden
Remnants of the base of the type 636 SK Leitstand bunker

The German Kriegmarine built a bunker type 636 SK Leitstand bunker here to direct the fire of the battery. This bunker was also an SK version, so an adaptation of the Regelbau type 636. After World War Two the upper part of the construction was torn down. The only thing left to see today is it’s subterranean base (picture above).

Underneath here is an example of a standard Regelbau type 636 Leitstand of Stutzpunkt Bruno on the beach at Zuydcoote France. The 636 SK of Fort Island IJmuiden would have hade a more square formed observation room.

Bunker regelbau 636 Zuydcoote France
Bunker R636 of Stp. Bruno at Zuydcoote France

Bunker Type 644 Stand mit 6-Schartenturm

Bunker Type 644 IJmuiden
Bunker Type 644 at Fort Island IJmuiden

There used to be four of these type 644 bunkers on the island, but the other three were demolished in 1967. The fourth disappeared under the sand for many years. But during the islands’ revival in 1994 the bunker was uncovered again. The 6 embrasured armored steel turret is unique for the Dutch Atlantic Wall.

6-Embrasured turret
The 6-Embrasured armored turret of the type 644 bunker

Brunnengalerie – Water supply bunker

Fort IJmuiden Brunnengalerie
The water supply bunker or “Brunnengalerie” in the dry moat of Fortress IJmuiden

This is a water supply bunker built into the IJmuiden Fortress moat. This bunker basically one long hallway. There is an outside entrance (triangular part) and a connection into the Fort.

After WW2

After WW2 Fort at IJmuiden and the Island lost it’s strategic importance and when the last two fortress guards left in 1964 it was completely abandoned. In 1967 the island was again altered to make more room for shipping, giving it the square shape it has today. Part of the fort and the German bunkers were demolished during this period.


Fort IJmuiden Noordzeekanaal
Fort IJmuiden seen from the main land

Nowadays Fort at IJmuiden has largely been restored and is open to the public on special visiting days organized by the “Fort at IJmuiden Association” and the WOVIJ foundation. These are mostly on Wednesdays and Sundays, where a boat will take you to the Island. You can choose to take a guided tour or just wander around and discover everything by yourself.

Look for the actual dates and times on the PBN website or (both these websites are in Dutch). Tickets for the Island crossing can be ordered by following the link.

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