Can a surfer use position or priority to stop a rival catching waves?
A · Advanced · Priority and interference · 2 of 4Only up to a point. A surfer who blocks another from a wave without trying to ride it, or who hassles a rival around the line-up, is dropped to the lowest priority. A priority surfer who paddles or takes off only to block loses priority. Hassling a surfer who holds priority can bring an interference penalty.
How it works
- Blocking without priority: a surfer with the inside position who makes a committed paddle and blocks another from the wave is given the lowest priority.
- Sitting in the way: positioning in the take-off zone to block another surfer has the same result.
- Hassling: a surfer who "excessively hassles, blocks or hinders another Surfer from paddling in the line-up" is given the lowest priority.
- Worse: "Aggressive or unsportsmanlike behavior may also result in an Interference Penalty 1."
- Blocking with priority: the priority surfer loses priority for paddling in front of an opponent to impede them.
- Or for position: for placing themselves in the take-off zone to prevent another surfer catching a wave.
- Or for a dummy take-off: for using priority on a wave "when the Surfer with priority appears to have had no intention to score".
- Leaving the zone: a priority surfer who goes outside the primary take-off zone has priority suspended.
- Hassling the priority surfer: excessive, unsportsmanlike hassling can bring interference penalty 2.
- Serious cases: an intentional interference that injures another surfer can mean a fine, disqualification from the event and suspension.
- Who decides: the priority judge and the head judge.
The glossary has the blocking and hassling entry, the priority entry, the priority judge, the primary take-off zone, the interference penalties entry and the lineup.
Tricky cases
A leading surfer with priority sits beside their rival for the last three minutes and takes no waves. Is that allowed?
Marking a rival is not banned as such. Paddling in front to impede them, positioning to prevent them catching a wave or leaving the take-off zone to follow them costs priority.
The priority surfer takes off on a small wave and steps off after a second, to keep it from a rival. What can happen?
They lose priority, and it can be awarded to the other surfer regardless of who gets back to the take-off zone first.
Two surfers have a paddle battle for the inside. Is that hassling?
Paddling for position is part of a non-priority heat. It becomes an offence when it is excessive in the judges' opinion.
Is losing priority the same as an interference?
No. Losing priority costs no points. An interference penalty takes away or halves a scoring wave.
Why the rule exists
Priority is meant to be a right to ride, not a weapon. Once a surfer is ahead, the obvious tactic is to sit on the rival and use position to keep them off every wave. These rules allow close marking and stop the cases where a surfer has plainly given up trying to score.
Where it differs
| Where | What changes | Source |
|---|---|---|
| Non-priority blocking | Lowest priority | ISA, Priority System 3 |
| Non-priority hassling | Lowest priority, and possibly penalty 1 | ISA, Priority System 4 |
| Blocking with priority | Priority lost | ISA, Priority System 5 |
| Hassling the priority surfer | Penalty 2 possible | ISA, Priority System 11 |
From the rule book
International Surfing Association, Rulebook and Contest Administration Manual (30 July 2026), Interference Rules and Priority: Priority System 3 to 5, 11 and 12. Checked 14 October 2026. Official document: ISA Rule Book, July 2026 (PDF).