Remain seated before the start of each race. Stand up on the Referee's short whistles.

For the start of freestyle, backstroke and butterfly events, one Judge should stand on the side of the pool at the 15-metre mark/false start rope. The other Judge should stand about halfway between the backstroke flags and the 15-metre mark/false start rope. For all events except freestyle, walk on the pool side in good view of the leading swimmers. For the backstroke, do not walk where you are staring into the faces of the swimmers. The breaststroke and butterfly are best judged by walking abreast or slightly behind the swimmers. Judges should walk at a pace that is sufficient to stay with the swimmers.

If the field of swimmers spreads out, the leading Stroke Judge should take jurisdiction over the leading swimmer(s). The trailing Stroke Judge should take jurisdiction over the slower swimmer(s). After each turn, the Stroke Judges switch jurisdictions as they begin to walk in the opposite direction. Teamwork and coordination are important between the 2 Stroke Judges. It ensures that they observe all of the swimmers in their half of the pool on a fair and equitable basis.

Give all lanes equal attention. Do not concentrate solely on the lanes closest to you.

Unless told otherwise by the Referee, judge only your half of the pool. Judge from the start of the race until the start of the last arm stroke on the approach to a turn, and from the completion of the first arm stroke after a turn through to the finish touch.

The Stroke Judge must be able to clearly watch submerged swimmers in the freestyle, backstroke and butterfly events after the start or each turn. They must ensure that the swimmers' heads surface before the 15-metre mark.

Meet Officials functioning as both Stroke and Turn Judges must walk the sides of the pool and position themselves over the ends of the pool before the first swimmer in their jurisdiction turns. This ensures they cover all aspects of the competition.

The Stroke Judges' responsibilities begin after the start. Any action before the start is the Starter's responsibility, or, for relay takeoffs, it may be the Relay Takeoff Judge's responsibility. Each Stroke Judge should be alert and observe the starting signal because his or her duties begin immediately there after.

Certain infractions are common to all strokes and include:

• Leaving the water before completing the full distance.
  
• Walking in the desired direction along the bottom of the pool.
  
• Springing from the bottom of the pool, if it imparts movement in the desired direction.
  
• Pulling in the desired direction on the lane ropes or the side of the pool.

FREESTYLE: Stroke Judging Mechanics

• Watch for any infractions common to all strokes.

BACKSTROKE: Stroke Judging Mechanics

• Watch that the swimmer remains on the back for the whole race, unless executing a turn.
  
• The shoulders may roll to the vertical.
  
• Watch for any infraction common to all strokes.

BREASTSTROKE: Stroke Judging Mechanics

• Watch that on the start and on each turn, the swimmer does not make a deliberate underwater "dolphin kick" or flutter kick followed by a "frog kick."
  
• Watch that on the start and each turn, the swimmer takes no more than the allowed one arm pull back to the hips and one leg kick underwater, in that order. Watch that the head surfaces before the hands have started inward at the widest part of the second stroke.
  
• Watch that when the swimmer surfaces at the start and each turn, the body is kept on the breast with both shoulders in line with the water's surface.
  
• Watch that the head surfaces once per stroke cycle. At this time, there must be no water flowing over the head.
  
• Watch that all movements of the arms are simultaneous and in the same horizontal plane. Watch that the hands are pushed forward together from the breast on, under, or over the water (with the elbows under the water except the final stroke at the finish), and brought back on or under the surface of the water. The elbows may be out of the water on the backward pull of the stroke.
  
• Watch that all movements of the legs are simultaneous and in the same horizontal plane and without alternating movement.
  
• Watch that the feet are turned outward during the propulsive phase of the kick. However, on the kick recovery, the legs may undulate in the water current without penalty.
  
• Watch for any infractions common to all strokes.

BUTTERFLY: Stroke Judging Mechanics

• Watch that at the start and each turn, the swimmer takes no more than one arm stroke while totally submerged. There is no limit to the number of kicks that may be executed.
  
• Watch that when the swimmer surfaces at the start and on each turn, the body is on the breast with both shoulders in line with the water surface.
  
• Watch that both arms are brought forward simultaneously over the water's surface.
  
• Watch that the arms are brought backwards through the water simultaneously.
  
• Watch that the legs do not alternate with each other ("flutter kick"). One leg is allowed to be carried higher than the other, if there is no alternating motion. The swimmer may also use the breaststroke kick ("frog kick") and may change back and forth without penalty.
  
• Watch that some part of the swimmer breaks the surface of the water throughout the race.
  
• Watch for any infraction common to all strokes.

MEDLEY RACES: Stroke Judging Mechanics

• Watch for any infraction common to all strokes.
  
• Watch that the competitors swim the strokes in the proper order.
  
• Watch that the competitors swim each leg according to the rules of that stroke.