Martina joins a list of new recruitments including the likes of Jordan Pickford, Michael Keane and Wayne Rooney.
The Curacao worldwide has signed a three-year contract with Everton.
"Everton is a big club with big ambitions and I'm really looking forward to joining this group of players and the manager as we try to step forward next season", the defender told Everton's website.
"Obviously, I know the manager from my time at Southampton, so I know what he wants and he knows what I can do".
With Seamus Coleman set to miss the start of the season with a broken leg sustained whilst on global duty with the Republic of Ireland against Wales earlier in the year, Martina's arrival will at least provide suitable cover at right-back.
Martina is part of the Everton squad travelling to the Netherlands for a pre-season and could make his first Toffees appearance against his former club FC Twente on Thursday.
Having made his debut against the Dominican Republic back in 2011, Martina has amassed 30 caps for the Caribbean nation of Curacao and he recently became captain.
"Everton supporters are really passionate about their Club and everyone's excited about where the Club is aiming".
'I brought the player to Southampton, so I know what he can do for us here and this is why I've now brought him to Everton.
Everton have been one of the busiest Premier League sides this summer.
Barkley has rejected the club's offer of a new contract and seems unlikely to sign a deal while Everton manager Koeman is targeting more players for the same position with Swansea's Gylfi Sigurdsson still on his wanted list.
"When you come to a new club, you need to get to know one another so the training camp in Holland will be great for me and for the other new players as well".