Does the 0.5 per mille car limit apply on a boat?

Structurally yes, on a different legal basis: § 1.02 BinSchStrO and § 3 SeeSchStrO prohibit operating a boat at 0.5 per mille blood alcohol or 0.25 mg/l breath alcohol or above, as an administrative offense – similar in structure to § 24a StVG for cars, but a separate set of rules with its own fine schedule. From 1.1 per mille onward it becomes a criminal offense.

What fine can you get for drinking and operating a boat?

Between 0.5 and 1.09 per mille it's an administrative offense: on inland waterways, fines typically range from 350 to 2,500 euros, and on coastal shipping lanes from 750 to 2,500 euros, depending on the case and authority. From 1.1 per mille, or with visible impairment at a lower level, it becomes a criminal offense under § 316 or § 315a StGB.

What consequences does a skipper face for operating a boat while drunk?

Anyone who is incapable of safely operating a vessel commits a criminal offense under § 316 StGB, even if nothing happens; if there is a concrete danger to others, the stricter § 315a StGB applies instead – negligent conduct under § 315a is punishable by up to two years imprisonment or a fine. Beyond that, you risk administrative fines, revocation of the Sportbootführerschein (since the inland and coastal ordinances were merged, the GDWS decides on revocation for both), and loss of insurance coverage.

Are passengers on a boat allowed to drink alcohol?

Passengers who aren't operating the boat are generally not bound to any specific BAC limit. But anyone scheduled to take the helm later, or who spontaneously takes over, becomes the skipper in a legal sense and must stay sober. On commercial passenger vessels, the crew on duty is held to a 0.0 per mille limit.

Blood Alcohol Limit on a Boat

Q: At what blood alcohol level is a skipper considered absolutely incapable of operating a vessel?

Under case law from Germany's regional higher courts (Oberlandesgerichte, e.g. OLG Karlsruhe), absolute incapacity for a vessel skipper is set at 1.1 per mille – regardless of whether any external signs of impairment are visible. From around 0.3 per mille, relative incapacity can already apply if additional signs are present, such as unsafe handling of the vessel or an accident.

Many recreational boaters assume that either the exact same alcohol rules apply on the water as on the road, or that there’s no fixed limit at all on a boat. Neither is quite right. German law does set a specific limit for skippers, structured similarly to the road traffic rule but resting on separate legislation – and past a certain point it becomes a criminal offense regardless of road traffic law. Whether you’re preparing for your Sportbootführerschein or already out on the water, knowing the rules can save you from serious consequences.

The 0.5 Per Mille Limit on the Water

In German road traffic, the rules are straightforward: the Straßenverkehrsgesetz (StVG) sets a hard threshold at 0.5 per mille (‰) for an administrative offense (Ordnungswidrigkeit). Novice drivers and those under 21 must stay at 0.0‰.

The StVG itself does not apply to recreational boats. But the water has its own fixed number: the Binnenschifffahrtsstraßen-Ordnung (BinSchStrO) prohibits, under § 1.02, operating a vessel on federal inland waterways with 0.5 per mille or more blood alcohol (or 0.25 mg/l or more breath alcohol). Vessels on coastal shipping lanes are bound by the same figure under § 3 of the Seeschifffahrtsstraßen-Ordnung (SeeSchStrO). On international waters (open Baltic Sea, North Sea beyond the coastal shipping lanes), the International Regulations for Preventing Collisions at Sea (COLREGs) apply; they don’t state a fixed number, but they do require the skipper to operate the vessel safely at all times.

Crossing the 0.5 per mille limit on inland waterways or coastal shipping lanes is, first, an administrative offense – similar in principle to the car rule, just under separate legislation with its own fine schedule instead of the StVG. From 1.1 per mille onward it becomes a criminal offense regardless of the administrative fine (see below).

What the Fine Actually Costs

The amount follows the current fine schedule for shipping and varies by waterway and case:

Inland waterways: fines between 0.5 and 1.09 per mille typically range from 350 to 2,500 euros.
Coastal shipping lanes: the usual range is 750 to 2,500 euros.

The exact amount depends on the responsible water police authority, the specific BAC level, and any prior offenses. For other costly violations on the water – from boating without a license to leaving the scene of an accident – see our article on fines and violations on the water.

Relative and Absolute Incapacity to Operate a Vessel

Once the alcohol level goes well beyond the 0.5 per mille administrative offense, you leave the realm of fines and enter criminal law. German criminal law distinguishes two forms of incapacity to operate a vessel safely:

Relative incapacity (relative Fahruntüchtigkeit) can be established under case law from around 0.3 per mille, provided that additional signs of impairment are present at the same time: erratic or unsafe handling of the vessel, an accident, unsteady movement, slurred speech, or other visible symptoms. In these cases, even a comparatively low BAC can support a criminal charge.

Absolute incapacity (absolute Fahruntüchtigkeit) is established by case law of Germany’s regional higher courts (Oberlandesgerichte, e.g. OLG Karlsruhe, which lowered its earlier threshold from 1.3 to 1.1 per mille in 2020) for vessel skippers. The courts deliberately aligned this figure with the 1.1 per mille threshold that applies to car drivers, since operating a vessel demands comparable coordination and reaction requirements to driving a car. Only for bicycle riders does absolute incapacity kick in later, at 1.6 per mille. From 1.1 per mille onward, a skipper is considered absolutely incapable of operating a vessel safely – regardless of whether any external signs of impairment are visible.

Beyond the fixed BAC number, the BinSchStrO requires the skipper (Schiffsführer) under § 1.02 to ensure at all times that they are capable of safely fulfilling their duties. This expressly includes the skipper’s own fitness to operate the vessel and applies even below 0.5 per mille, for example in cases of exhaustion or medication.

For professional mariners, the rules are considerably stricter: on commercial passenger vessels and when transporting dangerous goods, the crew on watch during the voyage must stay at a 0.0 per mille limit.

The Criminal Law Dimension – § 316 and § 315a StGB

A skipper who is incapable of safely operating a vessel, whether relatively (from around 0.3 per mille with visible impairment) or absolutely (from 1.1 per mille), already commits a criminal offense under § 316 of the StGB (“Trunkenheit im Verkehr”, driving under the influence) – even if nothing happens and nobody is concretely endangered. Mere incapacity while operating the boat is enough.

If a concrete danger to other people or property of significant value is added, for example because another boat narrowly avoids a collision, the stricter § 315a of the StGB (“Endangering Rail, Vessel and Air Traffic”) applies instead and takes precedence over § 316.

For the negligent form under § 315a – where the skipper could and should have recognized the danger but failed to – the penalty is imprisonment of up to two years or a fine. Deliberate endangerment carries a penalty of up to five years. § 316 itself carries imprisonment of up to one year or a fine, for both deliberate and negligent conduct.

If an accident occurs and someone is injured, additional offenses come into play: § 229 StGB (negligent bodily harm) or, in the worst case, § 222 StGB (negligent homicide).

How a Check Works in Practice

The water police carry out random checks or stop boats after noticing erratic handling. The first step is usually a voluntary breathalyzer test with a handheld device that measures breath alcohol in mg/l (the 0.25 mg/l mark corresponds to the 0.5 per mille limit under the BinSchStrO and SeeSchStrO). If the reading is borderline, there are signs of a criminal offense, or the breath test is refused, a blood test can be ordered, which is admissible as evidence in court. Where clear impairment is visible, police also document the skipper’s outward condition – gait, speech, coordination – as evidence of relative incapacity.

Consequences at a Glance

Operating a boat while impaired exposes you to several simultaneous risks:

Administrative sanctions: From 0.5 per mille, fines apply under the inland or coastal shipping fine schedule (see above), issued by the waterway authorities (Wasser- und Schifffahrtsbehörden).

Criminal prosecution: From 0.3 per mille with visible impairment, or from 1.1 per mille, a conviction under § 316 StGB is possible; with a concrete danger to others, § 315a StGB applies – with fines or imprisonment depending on the severity.

License consequences: A conviction for drunk boating can lead to the revocation of the Sportbootführerschein (SBF). Since the inland and coastal license ordinances were merged into a single ordinance, the Generaldirektion Wasserstraßen und Schifffahrt (GDWS), Germany’s central federal waterways and shipping authority, decides on revocation for both the SBF Binnen and SBF See. Beyond that, the driver licensing authority may review – and potentially revoke – your car driving license if it concludes that a boating-related alcohol offense raises doubts about your general suitability as a driver.

Insurance consequences: Most German third-party liability and hull insurance policies for recreational boats include clauses that exclude or severely reduce payouts if the skipper was under the influence at the time of an accident. In the worst case, you receive no compensation at all and remain personally liable for all damage caused to other boats, infrastructure, or third parties.

Who Must Stay Sober – and Who Can Drink

As a passenger or crew member on a recreational boat, you are generally not bound to a specific BAC limit. You are not the skipper and do not bear direct responsibility for the vessel.

However, there are important exceptions:

Anyone who is scheduled to take the helm later must remain sober enough to do so safely. This is especially relevant on multi-day sailing trips where watch duties are shared.
On vessels where watch keeping is required or expected, all watch officers are held to appropriate standards of fitness.
Anyone who spontaneously takes over the helm becomes, from a legal standpoint, the skipper at that moment – regardless of what they had to drink before.

The practical solution for group outings is the same as on the road: designate a sober skipper for the day. That person handles all navigation; the others can relax and enjoy themselves within reason.

Drugs and Medication – Also Relevant on the Water

Alcohol is not the only substance that can impair a skipper. Illegal drugs are treated the same way as alcohol under §§ 316 and 315a StGB – and for certain controlled substances, even trace amounts detected in a blood test can be sufficient to result in prosecution, without needing to establish a specific threshold.

Prescription and over-the-counter medications can also impair the ability to operate a vessel. Strong painkillers, antihistamines, sedatives, sleeping pills, and certain heart medications all carry warnings about impaired driving and operating machinery. That warning applies to boats as well. If in doubt, consult the prescribing physician or pharmacist before taking the helm.

What the SBF Exam Tests on This Topic

The ELWIS question catalog – the official question bank for the SBF Binnen and SBF See exams – includes questions on alcohol, fitness to operate, and the skipper’s legal responsibilities. Typical exam questions cover:

What are the skipper’s obligations with regard to their own fitness to operate the vessel?
What must a skipper do if they realize they are no longer capable of operating the vessel safely?
What legal consequences can result from operating a vessel while impaired by alcohol?

The core answer for the exam: the skipper is at all times responsible for the safe operation of the vessel. If impaired by alcohol, drugs, or illness, they must not take or retain the helm – regardless of whether a specific BAC number is reached.

For a broader overview of the most demanding topics in the exam, see our article on common mistakes in the SBF exam.

Conclusion

On the water, a fixed 0.5 per mille (or 0.25 mg/l breath alcohol) threshold applies as an administrative offense under the BinSchStrO or SeeSchStrO, with fines typically between 350 and 2,500 euros. From around 0.3 per mille with visible impairment, or at the latest from 1.1 per mille, it becomes a criminal offense under § 316 StGB, and under the stricter § 315a StGB if others are concretely endangered. The consequences range from administrative fines through criminal prosecution to loss of the boating license, the car driving license, and insurance coverage.

The simplest and safest rule remains: As skipper, you do not drink. Anyone who wants to relax with a drink passes the helm to a sober person in good time.

If you’re preparing for the SBF exam, the Boatpass app gives you access to all questions from the official ELWIS catalog – including skipper duties, fitness to operate, and conduct on the water – in a dedicated practice and exam mode.

Blood Alcohol Limit on a Boat – What Skippers Need to Know