What Side Do You Pass a Boat On? Right-of-Way Rules

Eric DawsonByEric Dawson Boats & Cruises

What side do you pass a boat on? For two power-driven boats meeting head-on or nearly head-on, each alters course to starboard, so they pass port-to-port, left side to left side. In a crossing situation, the boat with the other vessel on its starboard side gives way. When overtaking, no fixed passing side is prescribed; the overtaking boat must keep out of the way until it is finally past and clear.

On the Great Lakes, Western Rivers, or waters specified by the Secretary, a downbound power-driven vessel with a following current has right-of-way over an upbound vessel. In narrow channels, a vessel should keep as near as is safe and practicable to the starboard-side outer limit.

What Side Do You Pass a Boat on in Different Situations

In this meeting situation, vessels should follow the applicable rule governing their passage.

Overtaking works differently. When one vessel comes from more than 22.5 degrees abaft the other vessel’s beam, the overtaking boat must keep out of the way and stay clear until it is finally past and clear. No fixed passing side is set for that maneuver under the U.S. overtaking rule, so the duty is clearance rather than choosing a side.

Under the U.S. crossing rule, that vessel must keep out of the way, and when circumstances permit it should avoid crossing ahead. A practical way to read the rule is that the boat on your right normally has the right-of-way, while the other boat must hold clear.

Local waterway rules can add another layer. In these situations, vessels must follow the applicable local rules. Narrow channels also call for extra care, and vessels should follow the applicable channel rule when navigating them.

Rule 13 also matters when the situation is uncertain. If there is doubt about whether a vessel is overtaking, the vessel should treat the encounter as overtaking and act accordingly, which means keeping clear rather than forcing a side-by-side pass. For that reason, the answer to the headline question is usually not a single side for every case, but a rule set: port-to-port in head-on meetings, no fixed side in overtaking, and give way to the boat on your starboard side in crossing encounters.

Head-On Meetings Use Port-To-Port Passing

Boats meeting head-on should pass port-to-port.

Under U.S. Inland Navigation Rule 14, that port-to-port arrangement is the standard answer for a head-on meeting. The same basic rule appears in the International Regulations for Preventing Collisions at Sea, 1972, for vessels covered by those rules on the high seas and in connected waters navigable by seagoing vessels.

One narrow exception appears on the Great Lakes, Western Rivers, or other waters specified by the Secretary. There, a power-driven vessel proceeding downbound with a following current has right-of-way over an upbound vessel even in a head-on situation, and the downbound vessel proposes the manner of passage and starts the maneuvering signals described by Rule 34(a)(i), as appropriate.

For readers trying to apply the rule on the water, the key point is simple: head-on means both boats move right, not left. That keeps the meeting orderly and leaves each boat passing on the other boat’s port side unless a specific exception for those waters applies.

Situation Core Rule Exception or Limit
Two power-driven boats meeting nearly head-on Each alters course to starboard They pass port-to-port
U.S. Inland Navigation Rule 14 Standard head-on meeting rule Applies when there is a risk of collision
International rules under COLREGs Also require the starboard alteration Apply on the high seas and connected waters navigable by seagoing vessels
Great Lakes, Western Rivers, or specified waters Downbound vessel with a following current has right-of-way Downbound vessel proposes the passage

Another practical detail matters on those special waters: the downbound vessel does not merely benefit from the exception, it also initiates the passage plan. That means the usual head-on pattern still exists, but the current-based rule changes which vessel leads the exchange.

Accordingly, the safest shorthand is port-to-port for ordinary head-on meetings, with the Great Lakes and other listed waters treated separately. If the vessel is downbound with a following current in those places, the exception controls; otherwise, each power-driven boat turns to starboard and passes left side to left side.

Overtaking Has No Fixed Passing Side

Overtaking has no fixed passing side. The overtaking boat must stay clear and remain clear until it is finally past and clear.

Under U.S. Inland Navigation Rule 13, a vessel is overtaking when it approaches another vessel from more than 22.5 degrees abaft that vessel’s beam. A nighttime check points the same way: the overtaking vessel can see only the other boat’s sternlight, and neither sidelights.

Because the rule focuses on keeping out of the way, it does not assign a mandatory port-side or starboard-side passing route. Bearing changes after the encounter starts do not shift that duty, and the overtaking vessel keeps the responsibility to avoid contact until it is fully clear.

How to Handle the Approach

  1. Decide first whether the approach fits the overtaking definition in Rule 13.
  2. If there is doubt, treat the situation as overtaking and act accordingly.
  3. Hold clear of the vessel ahead and avoid assuming a fixed passing side.
  4. Keep the overtaking duty in force until the vessel is finally past and clear.

That rule matters on both inland waters and the broader COLREG framework, since the overtaking duty is the same core idea in each set. A vessel in front does not have to choose a side for the other boat to pass, and the overtaking boat cannot claim a right to cut across simply because the angle later changes.

Marine and Safety Tasmania states the point in plain language by saying a boat overtaking another boat may pass on either side, but must keep well clear. For a U.S. reading, the key legal point is the same: the passing route is not fixed by Rule 13, and safe separation stays with the overtaking vessel from start to finish.

Crossing Situations Turn on the Starboard Side

In practical terms, a boat that sees another power-driven boat on its right-hand side is the vessel that must act to keep clear.

Under U.S. Inland Navigation Rule 15, the give-way vessel follows the crossing rule. As a practical matter, a boat that sees another power-driven boat on its right-hand side should treat itself as the vessel that must act first.

What That Means on the Water

For a crossing encounter, the passing path is not a fixed port-to-port or starboard-to-starboard arrangement. Instead, the key question is which vessel has the other on starboard, because that vessel carries the duty to maneuver and create a safe gap.

Along with that basic rule, the Inland provisions include a river-specific exception on certain waters.

Stand-On Action Still Matters

The stand-on vessel also has a role if the other boat does not respond. Under the COLREG framework, it may take avoiding action by its own maneuver when it becomes apparent that the vessel required to keep out of the way is not taking appropriate action.

That means standing on does not freeze both boats in place. A vessel that initially stands on should still be ready to act if the crossing situation starts to turn unsafe, because collision avoidance remains part of the duty on both sides.

Narrow channels and fairways have their own requirements. Traffic separation lanes call for a different move, because crossing traffic should do so as nearly as practicable at right angles to the general flow.

Channel Discipline

Rule 9 governs narrow channels and fairways. That wording matters, since it does not demand a rigid track if conditions make a tighter run unsafe.

Small craft also face limits in those waters. A vessel less than 20 meters long, or a sailing vessel, must not impede a vessel that can safely navigate only within the channel or fairway, and no vessel may cross if doing so would impede one that is confined to that passage.

Traffic Lanes and Local Rules

In traffic separation schemes, a crossing vessel should make the crossing at as near a right angle as practicable to the general direction of traffic flow. That approach reduces time spent in the lane and fits the basic collision-avoidance duties that still apply in every case.

Special local rules can add more detail for harbors, rivers, lakes, or inland waterways, so long as they conform as closely as possible to the Navigation Rules. Those rules mean the practical answer is not always limited to the basic port-to-port pattern.

Local authority requirements can therefore affect how a boat should move in a specific waterway, even when the broad rule set stays the same. International rules apply on the high seas and connected waters navigable by seagoing vessels, while U.S. Inland Rules apply in U.S. navigable waters shoreward of the navigational demarcation lines and on the U.S. side of the Great Lakes.

How to Decide the Right-Of-Way

First identify the encounter, then match it to the rule that applies. A quick look at where the other vessel sits relative to your bow usually tells you whether the meeting is head-on, overtaking, or crossing.

Recognition comes before action because each situation has its own required move. Head-on encounters and overtaking situations require the action described above. Crossing situations shift the burden to the vessel that has the other on its starboard side.

Work Through the Decision

  1. Check whether the other vessel is coming directly toward you on a reciprocal or nearly reciprocal course.
  2. If the answer is yes, treat it as a head-on meeting and prepare to alter to starboard.
  3. Next, ask whether your boat is coming up from behind another vessel and closing faster, and remain clear until you are past and clear.
  4. Otherwise, decide whether the vessels are crossing and whether the other boat is on your starboard side.
  5. If the other vessel is on your starboard side, give way as described above.

After that first classification, check for any special rule that changes the result. Those rules may apply in these waters.

Another useful filter is vessel status. A vessel not under command, a vessel restricted in her ability to maneuver, or a vessel constrained by draft may not fit the ordinary give-way pattern, and a stand-on vessel may still need to maneuver as described above. In practice, the safest habit is to identify the encounter early, make a clear maneuver, and keep watching until the risk of collision is gone.

Finally, remember that local conditions can change the operational picture, and vessel traffic service regulations may also apply in certain areas. A boater who reads the encounter, checks the setting, and then acts promptly is far less likely to guess wrong about right-of-way.

Other Vessels and Collision-Prevention Duties

Lookout, speed, and timely action still matter even when one boat has priority. Priority never replaces the duty to watch, judge risk, and avoid collision.

Lookout and Speed

Every vessel must maintain a proper lookout by sight, hearing, and all available means suited to the conditions, so the operator can assess the situation and the risk of collision. Safe speed also remains required at all times, with the surroundings and radar-related factors taken into account when radar is fitted.

Restricted visibility adds another layer of care. Rule 19 calls for a speed adapted to the prevailing circumstances, and a vessel that detects another by radar must decide whether collision risk exists and take avoiding action when needed.

Stand-On Duties Still Matter

Even a stand-on vessel cannot wait blindly for the other boat to act. As noted above, it may act when needed.

That means right-of-way is not a shield against responsibility. A boat that initially has priority still has to stay alert, because the rules contemplate avoiding action when the other vessel does not respond as required.

Other Vessel Types

Rule 18 also reaches beyond simple power-driven encounters. It addresses responsibilities between power-driven vessels, sailing vessels, fishing vessels, seaplanes, and wing-in-ground craft operating on the water surface, while Rule 27 covers vessels not under command or restricted in their ability to maneuver and Rule 28 covers vessels constrained by their draft in the international rules.

General guidance also points in the same direction for craft that are harder to handle. Marine and Safety Tasmania summarizes the usual idea as power giving way to sail, while warning that the pattern does not always hold and that ferries and container ships can be difficult to maneuver, so judgment still matters in every meeting.

Frequently Asked Questions

What Side Do You Pass a Boat on When Two Power-Driven Boats Meet Head-On?

When two power-driven boats meet head-on or nearly head-on with a risk of collision, each must alter course to starboard so the boats pass port-to-port. On the Great Lakes, Western Rivers, or waters specified by the Secretary, a downbound power-driven vessel with a following current has right-of-way over an upbound vessel in that situation.

Can You Pass an Overtaken Boat on Either Side?

U.S. Rule 13 does not assign a fixed passing side for overtaking. The overtaking vessel must keep out of the way and remain clear until it is finally past and clear, and if there is doubt, it must assume it is overtaking and act accordingly.

Which Boat Gives Way in a Crossing Situation?

In a crossing situation, the boat that has the other boat on its starboard side must keep out of the way. If circumstances permit, it should avoid crossing ahead of the other vessel.

Does a Stand-On Boat Still Have to Avoid a Collision?

Yes. The COLREGs say a stand-on vessel may take avoiding action by its own maneuver as soon as it becomes apparent that the vessel required to keep out of the way is not taking appropriate action. Holding the stand-on position does not remove the duty to avoid collision.

What Changes in a Narrow Channel or Traffic Separation Scheme?

In a narrow channel or fairway, a vessel should keep as near to the outer limit on its starboard side as is safe and practicable. Beyond that, in a traffic separation scheme, vessels crossing traffic lanes should do so as nearly as practicable at right angles to the general direction of traffic flow.

Do Local Rules Override the Basic Passing Rule?

Special rules made by an appropriate authority for harbors, rivers, lakes, or inland waterways connected with the high seas may apply if they conform as closely as possible to the Navigation Rules. Vessel traffic service regulations may also be in effect in some areas, so the basic passing rule is not always the only instruction that matters.

The main answer is simple: head-on meetings are port-to-port, overtaking has no fixed side in the U.S. rule, and crossing situations turn on which vessel has the other on its starboard side. Even then, the basic rule can give way to narrow-channel requirements, traffic separation schemes, and local regulations. A prudent boat operator also has to maintain a proper lookout, proceed at a safe speed, and take action when collision risk appears.

References

Sources read in September 2026.

Eric Dawson

I'm Eric Dawson, and I write The Money Watch from north Columbus, Ohio. Most of what I cover comes from my own life: renting, a 2014 Honda Fit, parking, computers, food and the bills behind all of it. I spent four years in an apartment-property office and eleven on a distributor's operations desk, reading leases and invoices. Where you need real information, I research the maker's or agency's own page and independent sources and report what they publish. I don't give tax, investment, legal or medical advice.