Swimming in the vicinity of ship traffic

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​​​​Swimming where there is ship traffic may be risky. It is difficult for ships to spot swimmers in the water, and sudden evasive actions may increase the risk of collision, allision or grounding.

Are you required to have a permit?

If you yourself intend to swim in our waters, or if you are to arrange swimming for others, you are not normally required to apply for a permit from the Danish Maritime Authority unless the event has an extent that may affect navigational safety or freedom of navigation. In that case, the Danish Maritime Authority will consider the case and ships will be informed through Notices to Mariners.

We seldom establish special swimming areas

If you intend to arrange a swimming event, you must first and foremost be aware that the Danish Maritime Autority does not normally impose restrictions on freedom of navigation. Normally, it will thus not be possible to establish areas with prohibitions against sailing due to swimming events.

Aids to navigation

Any marking of the swimming route will be made following approval by the Danish Maritime Authority.

It is difficult to spot swimmers

Please be aware that, from a ship, swimmers are very difficult to spot in the water. In narrow waters, large ships must not be brought in a situation where they will suddenly have to make evasive manoeuvres in relation to swimmers.

Notification of ships

In connection with swimming events in trafficked waters, you must in general forward information about the event no later than six weeks in advance to sifa@dma.dk containing details about when, where, how many, swimming route, etc. so that ships are informed well in advance.

Swimming outside Danish waters

If the event starts or ends outside Denmark, you should enquire about the relevant country's regulations.

International ship traffic separation systems and deep-water routes

Swimming in a traffic separation system and deep-water routes plotted in charts is prohibited. The Danish Maritime Authority cannot, in consideration of navigational safety, accept the arrangement of swimming events that will cross traffic separation systems or are closer than two nautical mile from the ends of a traffic separation system or deep-water routes.

Areas with Vessel Traffic Service (VTS)

If a swimming event takes place within a VTS area, the event will be arranged in cooperation with the VTS centre in consideration of navigational safety. (VTS Sound: +46 771 630600/ CONTACT@soundvts.org - VTS Great Belt: +45 58 37 68 68 / BELTREP@mil.dk.)

Crossing ships' routes

Traffic routes, fairways or navigation channels should be crossed perpendicularly to the direction of operation so that the swimmers pass as fast as possible.

Cancellation or changes

In case the event is cancelled or interrupted, please inform the VTS and the Danish Maritime Authority as soon as possible.

Carry out only in clear weather

Where there is ship traffic, you should swim only in the day-time and only in clear weather.

Wind, current and weather

Examine conditions related to weather and current before starting (for example by means of the webpage of the Danish Meteorological Institute, www.dmi.dk (Danish only)).

Accompanying boats

Ensure that there is sufficient capacity in the accompanying boats at any time to take on board swimmers if this should become necessary due to ship traffic or swimmers.

Get an overview

An overview of the area is important. Since other ships cannot be expected to show special consideration of the participants in the event, you should ensure that the accompanying boats have an overview of the situation in the area all the time, including ships entering and leaving ports.

Swimmers may get in distress. Accompanying boats should be ready at any time to take on board swimmers and carry out remedying measures in case of dangerous situations with ships navigating the areas or if the swimmers are in difficulties.

Stay with the swimmers

Do not leave swimmers in places with ship traffic without the presence of an accompanying boat.

Inform about the event

Inform the authorities about the event, such as bridge watches, VTS, port authorities, the police, pilots and the like in the vicinity of the area.



Safety of Navigation, National Waters
Sikre farvande
+45 72 19 60 00