What is an interference in surfing?
I · Intermediate · Priority and interference · 4 of 4Hindering the scoring potential of a surfer who has the right to the wave. It can happen on the wave, by riding in front of them or crossing their path, or before it, by blocking them as they paddle. It is called only when a majority of the judges mark it.
How it works
- The test: whether a competitor "has hindered the scoring potential" of the surfer with right of way or priority.
- A majority: "An interference penalty can only be called if a majority of the judging panel marks an interference".
- The head judge: may call it only if the panel could not reach a majority, or did not see the incident.
- With priority: crossing in front of the priority surfer, or bottom turning round them, in a way that hinders their scoring potential.
- Even while they are paddling: the rule applies whether the priority surfer is up and riding or still catching the wave.
- Paddling interference: making contact with the inside surfer, blocking them physically or causing a section of the wave to break down in front of them.
- Paddling out: a surfer paddling back out who cannot get out of a rider's way is not penalised. One who could have avoided it may be.
- Other examples: excessive hassling and leash pulling.
- The ride scores zero: a wave on which a surfer interferes is scored zero.
- No argument: "The Judges will not enter into any discussion over the interference call."
- After the wave limit: a surfer who has used up their waves and then gets in the way of another receives an interference.
The glossary has the interference entry, the paddling interference entry, the right of way entry, the priority entry, the judges and the head judge.
Tricky cases
A surfer without priority takes off in front of the priority surfer, sees them and kicks out at once. Is that an interference?
It depends on whether the priority surfer's scoring potential was hindered. If the judges find it was not, there is no penalty.
Two surfers bump shoulders paddling for a wave and the inside one still catches it cleanly. Penalty?
Probably not. Paddling interference needs the inside surfer to have been hindered, with a possible loss of scoring potential.
A surfer paddling back out is caught in the path of a rider and cannot move. Who is at fault?
Nobody. A surfer with no ability to remove themselves from the rider's line is not penalised.
Can a surfer argue the call with the judges?
No. Once made, an interference decision can be changed only by the head judge, and only if it rested on faulty video or audio.
Why the rule exists
The measure is the other surfer's score, not contact. Two surfers can touch without either ride being spoiled, and a surfer can ruin a ride without touching, by taking the line the other needed. Requiring a majority of judges keeps a heat from turning on one judge's view of a crowded moment.
Where it differs
| Where | What changes | Source |
|---|---|---|
| Non-priority situations | Hindering the surfer on the inside | ISA, Right of Way ii |
| Priority situations | Hindering the surfer with priority | ISA, Priority System 1 |
| Paddling | Contact, blocking or breaking a section | ISA, Paddling Interference b |
| Surfers from another heat | Paddling in or out, with a possible re-surf | ISA, Paddling Interference d |
From the rule book
International Surfing Association, Rulebook and Contest Administration Manual (30 July 2026), Interference Rules and Priority: Application, Paddling Interference, Priority System and Interference Penalties. Checked 14 October 2026. Official document: ISA Rule Book, July 2026 (PDF).