Most open water swims in the U.S. are between 1 kilometer and 3 miles.

Below is some kind of FAQ for those not familiar with open water swimming:

On longer distance, do swimmers eat or drink?

feedingIn most open water swims, feeding and hydration are not absolutely necessary, especially when the race is under 3.1 miles (or 5 kilometers). However, in case of swims longer than 5K, hydration and feeding are an essential element of success.

Feeding and Hydration: What and When
A 5K race can take between 50-60 minutes, depending on the conditions. A 10K race will take between 1 hour 50 minutes and 2 hours. A 25K race can take between 5 and 7 hours. Swimmers take a wide variety of liquids and gel packs during races above 5K.

Liquids include Gatorade, flavored water or water. Food includes primarily gel packs, although a variety of foods are also occasionally consumed in races longer than 10K.

Feeding can be described in four stages as the swimmers come in and out of the feeding area:

Seek and Spot
Reach and Roll
Gulp and Go
Toss and Turn

What are racing styles, strategies? How races are finished

finishFinishes are nearly always a fierce battle where swimmers are sprinting with everything they have. Often lane lines or ropes help funnel the swimmers toward the finish line or touch pads.

There are 3 different general types of finishes: (1) floating pontoon finishes with touch pads that are used at Olympic and world championship races, (2) in-the-water finishes where the finish line is indicated by a rope or other marker, and (3) run-out-of-the-water finishes used on many races on the East and West coast.

In FINA and major international races, the finish is a specially constructed floating pontoon with 6 touch pads elevated above the surface of the pad. The touch pads are supported by a special floating pontoon that is anchored at the finish line. Swimmers must clearly touch one of these elevated touch pads to officially finish.

Swimmers should remember to strongly touch any one of the finish pads, preferably with the palm of their hand. Merely crossing the plane of the touch pad is not an official finish. The touch pad must be visibly touched by one’s hand. Even if an athlete swims past the touch pad, he or she must reach up to touch the pad for an official finish.

Swimmers should time their final stroke so their palm or outstretched fingertips hit the touch pad before their body crosses the plane of the finish. This must be practiced over and over again because so many international races are decided in the last few meters and some races come down to the final stroke. Touch pads are above the surface of the water.

Swimmers should take a straight line to nearest touch pad. Swimmers can touch any pad of the 6 pads. Think of 3 pool swimmers finishing a race in the same lane in a pool, immediately followed by 5 other swimmers also in the same lane. This will give you an idea of how close and how competitive FINA-sanctioned international races are.

The finish at FINA and many international races are video taped for photo finishes. Photo finishes are quite common in international competitions, especially among the top 10 finishers.
Swimmers and coaches should know that the official placing is decided by finish judges – either by their own eyes or upon a post-race review of the finish as captured by the cameras. There are three judges positioned at the finish line responsible for this final decision.

To give you an example, there was a race at the 2004 World Open Water Swimming Championships in Dubai that was decided using all four processes. As the Dutch and German swimmer sprinted stroke-for-stroke to the finish over the last 200 meters, synchronized with their stroke count and breathing patterns, the crowd anticipated a photo finish. Neither of the athletes was able to drop the other. Towards the final few meters, the two swimmers simultaneously raised their heads looking up toward the touch pads. They both reached up to the touch pads at the same time with their leading hand…only to miss the touch pads in their final lunge. As the momentum of the swimmers carried them across the plane of the goal, they both extended back with their rear hands to simultaneously hit the touch pads.

The transponders were triggered when the swimmers slapped the touch pads at the same time. The Dutch supporters cheered in victory – and so did the German fans. The rest of the crowd yelled in excitement and then became strangely quiet because no one knew the winner. Fortunately, the video cameras caught everything on tape and the judges went into a deliberation room where they stay for a few hours before the Dutch swimmer was declared the winner.

After finishing the race, swimmers should move past the touch pad to exit the water. The two transponders on the swimmers’ wrists are removed by the officials immediately after race.

Similar to pool swimmers at major international competitions, all swimmers must pass through the Mixed Zone after the race. The top swimmers will be interviewed by the media. USA Swimming officials with press credentials may also be there to assist the American swimmers.