What are the measurements of a competition pool?
Officials' detail · Penalties, kit, records and the pool · 2 of 2Championship pools are 50 m long, measured between the touch panels, with a tolerance of one centimetre. Short-course pools are 25 m. At the Olympic Games the pool is at least 2.5 m deep with eight lanes 2.5 m wide. The water is kept between 25 and 28 degrees Celsius.
How it works
- Length: 50.000 m or 25.000 m between the touch panels. The tolerance with panels fitted is plus 0.010 m and minus nothing.
- Width: at least 25 m for a permanent pool at the Olympic Games and World Championships.
- Depth: at least 2.5 m at the Olympic Games and World Championships. At other World Aquatics events at least 1.0 m, and 1.35 m near the wall where starting platforms are used.
- Lanes: eight lanes 2.5 m wide at the Olympic Games, with a strip 2.5 m wide outside the first and last.
- Lane ropes: they separate the lanes and damp the waves. The floats are red for the 5 m at each end and a different colour at the 15 m marks.
- Starting platforms: firm, with no spring, 0.5 m to 0.75 m above the water, numbered on all four sides.
- Backstroke flags: ropes of flags across the pool, 1.8 m above the water and 5 m from each end wall.
- Lines: a dark line along the floor in the centre of each lane, ending 2 m from each wall in a cross line, with a target line on each end wall.
- Temperature: "The water temperature must be between 25.0° and 28.0° Celcius."
- Still water: the surface must be level with no appreciable movement.
- Light: at least 1500 lux over the whole pool at the Olympic Games and world events.
The glossary's pool entry gives the long-course and short-course lengths.
Tricky cases
Can a pool be 49.99 m long?
No. The tolerance allows a pool to be up to 1 cm long and not short at all.
Why are short-course times faster?
Because a 25 m pool has twice as many turns, and a swimmer is fastest pushing off the wall. The rules reflect that by keeping separate records for 25 m pools.
Is every competition pool 2.5 m deep?
No. That depth is required at the Olympic Games and World Championships. Other events may use shallower pools.
What are the flags over the pool for?
They are backstroke turn indicators, 5 m from each wall, so that a swimmer on their back can judge the distance to the wall.
Why the rule exists
Times from one pool are compared with times from every other, so the pool is built to a centimetre and never short. Depth, wide lanes and the empty outside strips all cut down the waves that bounce back at swimmers. A fixed temperature range keeps muscles working without overheating in a long race.
Where it differs
| Where | What changes | Source |
|---|---|---|
| World Aquatics rules | As above | SW 15.1 to 15.13 |
| World Championships (25 m) | At least 2.0 m deep | SW 15.4.2 |
| Ten-lane pools | The middle eight lanes are 2.5 m wide | SW 15.6.2 |
| Other competitions | No minimum width, and lighting of at least 600 lux over the platforms and turning ends | SW 15.3.2; SW 15.12.2 |
From the rule book
World Aquatics, Competition Regulations, Part Two: Swimming Rules (in force as from February 2026), Article 15. Checked 14 October 2026. Official document: World Aquatics Competition Regulations (PDF).