"But we are respectful and mindful to what the Japanese way is. We will be making sure that what we are showing will be OK."
The skin suits will not be needed during games but they will be used at other venues.
Samoan are in Pool A with Japan, Scotland, Ireland and Russia.
Tattoos have long been associated with criminal organisations in Japan, their so-called mafia, and people wearing them can be prevented from entering public places like pools and beaches.
Samoan manager Va'elua Aloi Alesana said every boy, at a certain age, gets a tattoo "as a kind of passport to get into the group and serve the chiefs."
"Our view is that we have to respect the culture of the land we are in wherever we go. We have our own culture as well but we are not in Samoa now," Aloi Alesana said.
"There are some training venues that have allowed us to show our tattoos and some places where we can't, and for those places, we've been given 'skins' to wear to cover our tattoos.
"The extra skins are only for when we go to the (swimming) pools though, at the training we can wear our normal clothes."
One of Lam's tattoos is a woman's face behind a big rose. Other players have more traditional markings. It is a custom that goes back thousands of years in the Pacific Island nation.
The All Blacks are also covering up when asked, although the rules change from place to place. Their hotel allows tattoos to be shown.
World Cup tournament directors Alan Gilpin said teams had shown "huge goodwill" towards the Japanese culture.
"Many of the teams are very understanding of that and will be covering with various items of clothing," Gilpin said.
But there is no directive to cover up on the field. Some Wallaby players have reportedly used rash vests while in public pools.
