Swimming Rules: What Actually Gets a Swimmer Disqualified

A note on rule numbers

If you have looked this up before, you may have seen rules cited as SW 5.3 or SW 10.4. Those codes came from FINA’s separate Swimming Technical Rules booklet.

World Aquatics has folded that booklet into a single Competition Regulations document, and the numbering changed with it. Every citation below is to the current version, dated 18 February 2026. Any page still quoting SW codes is working from a superseded document, which is a reasonable first test of whether a swimming rules page has been checked recently.

The 15-metre rule

This is the rule that decides the most races and causes the most confusion.

A swimmer may be completely submerged during a turn and for no more than 15 metres after the start and after each turn. By the 15-metre mark, the head must have broken the surface.

Stroke	Article	15-metre limit
Freestyle	5.3	Yes
Backstroke	6.3	Yes
Butterfly	8.6	Yes
Breaststroke	7.1	No — different rule entirely

The rule exists because underwater dolphin kicking is faster than surface swimming. Without a limit, the optimal way to swim a 50m freestyle would be to not swim it — and the sport decided that a swimming race should involve swimming.

Note what is measured. It is not how long you stay under, or how deep. It is distance from the wall, which is why lane ropes carry a distinct float colour at the 15-metre mark and why officials sight along that line.

Breaststroke is the exception, and always has been

Breaststroke has no 15-metre allowance. Its underwater phase is defined by movements, not distance.

Under Article 7.1, after the start and each turn a swimmer may take one arm stroke completely back to the legs, during which they may be submerged, and one butterfly kick is permitted at any point before the first breaststroke kick. The head must break the surface before the hands turn inward at the widest part of the second stroke.

That single permitted butterfly kick is a relatively recent concession, and it is exactly one. A second one is a disqualification, which is why breaststroke pullouts are watched more closely than almost anything else in the pool.

The start, and what “may” means

Article 4.4 reads: any Athlete who initiates a start before the signal may be disqualified.

Swimming is often described as having a one-start rule with automatic disqualification. The regulation is more procedural than that, and the timing matters:

If the starting signal has already sounded (4.4.1), the race continues, and the swimmer is disqualified at the completion of the race. Nobody is called back.

If the disqualification is declared first (4.4.2), the signal is not given, the field is stood down with the command “stand down please”, and the referee restarts the procedure from the long whistle.

So a swimmer can be disqualified and still be required to swim the whole race — and the rest of the field swims a real race alongside someone whose result will not count. It avoids the far worse outcome of recalling a field that has already dived.

The medley orders are different, and it is not arbitrary

This catches people constantly, including commentators.

Event	Article	Order
Individual medley	9.1	Butterfly → Backstroke → Breaststroke → Freestyle
Medley relay	9.2	Backstroke → Breaststroke → Butterfly → Freestyle

The reason is backstroke is the only stroke started in the water. A backstroke leg cannot begin with a dive from the block, so it cannot follow another swimmer in a relay changeover.

Put backstroke first and the problem disappears: the opening swimmer starts in the water holding the wall, and every subsequent leg dives normally. The individual medley has no changeovers, so it is free to use the order the sport considers hardest-first.

There is also a neat trap in Article 9.3. During the freestyle section of a medley, a swimmer may leave the wall on their back, but no kick is permitted until they have returned past the vertical to the breast. Turning early is legal; kicking early is not.

The finish, and the 5-metre mark

The mirror image of the 15-metre rule sits at the other end of the pool.

Once part of the swimmer’s head has passed the 5-metre mark before the finish wall, they may be completely submerged. That is why swimmers put their head down and drive through the last stroke without breathing — it is permitted, and it is faster.

Both butterfly (8.5) and breaststroke (7.7) additionally require the finish touch to be made with both hands separated and simultaneously. A one-handed touch at the wall ends races.

Reading them yourself

World Aquatics publishes the Competition Regulations openly, and they are revised more than once a year — the current version is dated February 2026, with several 2024 and 2025 versions archived behind it.

That revision pace is the real reason so much swimming rules content is wrong: it was accurate when written and nobody went back. The same problem affects the laws of golf and table tennis service rules, where a governing body’s periodic rewrite quietly invalidates a decade of published explanations. More rules coverage is in rules and techniques.