If a player is in front of a team-mate in possession of the ball, or in front of their team-mate who last played the ball, they will be offside if:
They move towards the opponents or the place where the ball lands without first coming back onside
The referee will award a penalty at the place where the offence took place.
Offside after a tackle
Once a tackle has been made and completed, the referee will tell the team without the ball to get back 10m from the ball.
Only two players is allowed within the 10m and they are called the "markers".
Every other player must be behind the marker and 10m from the ball.
If they are not, the referee will award a penalty to the team with the ball.
If the attacking team are less than 10m from the try line, then the referee will tell the defending team to get behind the try line.
Offside at a kick
If one of your team-mates is about to kick a high up-and-under or a grubber kick to run onto, make sure you are level or just behind them when they kick.
If you are not, the referee will award your opponents a penalty because you are offside.
The rules say that to be onside at a kick, an active player not in possession of the ball, must be behind the player who kicks the ball.
If you are in front of the kicker, make sure you don't get involved with open play.
You can do this by raising your arms and running back to an onside position.
This shows the referee you have no intention of joining play because you know you're offside.
However, if you make no attempt to move back to an onside position as play continues, the referee will award a penalty to the opposition.