Seacoast Dock Dogs and the Dock Dogs competition returns to the Union Fair.

The competitions are Saturday, Aug. 17 and Sunday, Aug. 18, starting each day at 8 a.m.

Dock diving is a performance sport that is all about fun for dogs, owners and spectators.

Big Air is the most popular discipline, as this is what most people think of when they hear the term dock diving. In Big Air, the dog runs down the dock and jumps out for a toy that has been thrown into or out over the water. The measurement is taken at the point at which the base of the dog's tail (where it meets the body) hits the water. With 90 seconds to execute each jump, the team is given two jumps in each wave with the longer of the jumps being their official score for that wave.

Extreme Vertical is a discipline that has the dog jumping up to grab a bumper. In Extreme Vertical, a Dock Dogs bumper is suspended from an extender 8 feet out from the dock and at heights ranging from 4-feet, 6-inches up to as high as a dog can jump. (The current record is 8 feet) The bumper is moved up in increments as the participating dogs execute the jumps.

The dog begins his run anywhere in front of the 20 foot line on the dock and has 60 seconds to complete each jump. The bumper must be either snatched cleanly or completely knocked down into the water by the dog in order for the jump to count. Each dog has two chances to grab the bumper.

Speed Retrieve is the newest of the dock diving disciplines. A Dead Fowl Trainer (DFT) is hung at the end of the pool (or 38-feet from the dock in a body of water). The dog is set by the handler at the 20 foot mark on the dock. When the signal is given, the timer starts and the dog is released. The dog runs down the dock, jumps into the water, and swims down to the DFT. When the dog grabs the DFT and pulls it down, the timer stops

If the dog begins his run and crosses the 20 foot line before the signal is given, it is considered a false start and the run does not count. The handler has 90 seconds to execute the run. Each team is given two runs in each heat with the faster of the two runs being the official score for that wave.

The Union Fair runs from Aug. 17-24. For a complete schedule and admission options please visit unionfair.org.