Yontaifib is an elite unit in the Marine Corps, just like Kopassus in the Army. This unit is used to be named Kipam (Komando Intai Para Amfibi - Amphibious Reconnaissance Special Forces Command).
To obtain a certification of amphibious reconnaissance, a regular Marine has to first pass a tough selection and then pass the nine-month rigorous training program that contains the most difficlut curriculum. Thus, this amphibious recon certificate is very similar to commando certificate in Kopassus.
To become a Yontaifib troop, a candidate is selected from the Marine Corps who has already fulfilled the thorough mental and physical requirements, and who at least has actively served the corps for two years. The certification of amphibious reconnaissance is so difficult that the passing rate of these candidates in each class is only ten percent.
One of the most challenging exercise in this certification program is to swim underwater for three kilometers with the hands and feet are all tied. Because they are tied, the swimmer has to mimic the way dolphins swim. This swimming style is a training for anticipation of being caught by the enemies and trying to escape by swimming in the river or sea. The escape experience by U.S. Navy Seal members in the Vietnam War is the basis for this training.