By Karolos Grohmann

RIO DE JANEIRO (Reuters) - Five sports, including baseball, skateboarding and surfing, will feature at the 2020 Tokyo Olympics after the IOC voted them in on Wednesday in an attempt to revamp the Games program to attract a younger audience.

The International Olympic Committee unanimously rubber-stamped the decision taken by its executive board in June, approving the inclusion of skateboarding, surfing, sports climbing, karate and a joint baseball/softball bid, which is expected to significantly boost local support for the Olympics.

The IOC session in the Brazilian city voted unanimously with a show of hands in favor of the sports which will make a one-off appearance in the Games.

"This will help make the Tokyo Games one of the most innovative Games in history," IOC Vice President John Coates said.

Baseball and softball, proposed to be staged in Yokohama, will each have a competition involving six teams. They last featured at the Olympics in Beijing in 2008 before being taken off the program and missing the 2012 and the 2016 Games.

It is unclear, however, if baseball will feature the world's best players from the MLB in the United States.

"Today’s historic decision by the IOC is a 'home run' for the Olympics, our sport and the Tokyo 2020 Games," World Baseball and Softball Confederation President Riccardo Fraccari said.

"Nations competing for the Olympic gold medal in baseball and softball, in Japan, will best showcase the nature and spirit of our global sport -- and it will be the most covered and most exciting international baseball/softball tournaments in history."

As part of sweeping reforms initiated in 2014, hosts can bring in sports popular in their countries to boost ratings and attract greater sponsorship as well as a younger generation of fans.

"I am so happy and so thrilled and I my have lost some of my composure," Tokyo Games chief Yoshiro Mori said. "This was an epoch-making decision today."

Surfing, with 20 men and 20 women athletes, will take place in the sea, instead of on artificial waves, likely in the Prefecture of Chiba. Skateboarding, with two street and two park events involving 40 competitors each (20 male, 20 female), will be in Tokyo.

"This is a game-changing moment for surfing," said international federation president Fernando Aguerre.

"We are already seeing increased popularity of the sport across the world and the Olympic Games will provide an incredible platform to further showcase surfing."

Karate could use the Nippon budokan -- home of Japanese martial arts -- and will have two events (one men's and one women's) for kata and three weight classes for kumite.

Sports climbing, also in urban Tokyo, will feature men's and women's competitions for bouldering, lead and speed combined with a total of 474 athletes to compete in the five sports.

Venues are to be finalised by the end of the year, Mori said.

(Editing by Ed Osmond)