What is Beach Ultimate?

From the WFDF Rules of 5-on-5 Beach Ultimate (2013):

Beach Ultimate is a five-a-side team sport played with a flying disc. It is played on a rectangular field, about half the width of a football field, with an end zone at each end. The object of each team is to score a goal by having a player catch a pass in the end zone that they are attacking. A thrower may not run with the disc, but may pass the disc in any direction to any team-mate. Any time a pass is incomplete, a turnover occurs, and the other team may take the disc to score in the opposite end zone. Games are typically played to 13 goals and last around 45 minutes. Ultimate is self-refereed and non-contact. The Spirit of the Game guides how players referee the game and conduct themselves on the field.

From Paganello Tournament:
Beach Ultimate is really easy: 5 players, a field of 75 meters long and 25 width with two opposite end zones. As in rugby, you score when a player get the Frisbee in the end zone. The difference is that you cannot walk with the Frisbee in your hand, you have only 10 seconds to throw it and the physical contact is almost absent. Have you ever seen it? Till now, have you been thinking that the Frisbee was only played with your dog? This is not true. Come to Paganello and take a look! You will be surprised of the atmosphere, the colors and matches played without referee. Yes, without referee. The players, they referee by themselves in a fair played game and respect of the rules, unlike the most famous and popular sports.

Via USAU:
Beach Ultimate is a popular and fast-growing spin-off of the grass-based game. Well-established Beach Ultimate events date back to the early 1990's, with some events hosting as many as 100 teams, making them some of the largest tournaments in Ultimate. Beach Ultimate leagues and casual pickup games are sprinkled across the country, even on lakeside beaches.

Beach Ultimate is played as 4-on-4 or 5-on-5 and is played by Mixed, Women, Open, Masters, College, and Junior level players and teams. Windy beach conditions and a smaller field demand a more precision-oriented set of throwing skills, while the sandy field requires even greater endurance.

Per BULA President Patrick van der Valk in BULA's documentary:
The feeling you get when you start to play beach ultimate is...you get to the beach and you take off your shoes. Instead of when you get to the field, and you put on your cleats. And I think that sorta changes people's thinking and feeling when you're on the beach.

It's...slightly more free. Therefore, the way people are playing is a very happy way of playing because you have no footwear. You just have your shorts and tshirt. You run and you smell the sea. There's the wind and the sun. And, it already makes you already happy playing the game. [15:30]