In Play Trading on Betfair is different from trading because it refers to trading the price of a horse or team while the race or match is actually running or playing.

When a race starts, Betfair suspends the market, cancels all unmatched bets and reclassifies the race market as In Play. Users can then place bets on the horses in the race as the race is running, up until the winner crosses the finish line.

In Play prices are much more volatile than prices are before the race starts because they are directly affected by each horse's performance during the race.

In Play traders watch the race or match unfolding and Lay and Back accordingly, trying to lock in profits by correctly reading what is happenning in the race or match.

Betfair's In Play markets allow skillful race readers to profit from Laying a tiring favourite midway through the race, or Backing a tennis player who gets off to a good start. Never before have gamblers had so many opportunities to make money in so many different ways from sporting events that until recently had a very limited number of betting products available on them.

Betfair imposes a 1 second delay on bets that are submitted into In Play horseracing markets, and a 5 second delay on bets that are submitted into In Play sports markets. This is to prevent people that are watching the event live from taking unfair advantage of the majority of people who view sports pictures that are delayed by a few seconds.