"I'm delighted to sign for this fantastic club - it's a good day for me", said Gomes to Everton's in-house TV channel.
Portugal global Gomes endured even greater struggles at LaLiga's champions and has found an escape route in the shape of a season-long loan at Goodison Park, which will cost the Toffees €2.25million.
Meanwhile, Lucas Digne left Barça to sign for Everton earlier in the summer.
The Toffees lured two more of the Catalan club's players to Goodison Park on permanent and loan deals respectively on Thursday.
"I know about Everton's players and I look forward to being able to play with my new team". A loan move for Chelsea's Kurt Zouma was also being worked on after a deal sheet was submitted to the Premier League for the defender.
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The experienced Maurizio Sarri is the latest incumbent in the Chelsea hot seat having replaced Antonio Conte last month. And it has been claimed the forward could leave Arsenal on deadline day in order to play more football next season.
Everton kick off their new Premier League campaign with a trip to Molineux to take on Wolves tomorrow, and Silva's men will have to be at their very best, if they are to return to Merseyside with anything to show for their efforts. When I found out about this opportunity and what the manager wanted out of me I was happy.
'Marco's words helped me a lot because having a coach who believes in his ideas is important. Despite interest from Manchester United and Lyon in the 23-year-old, and a six-week pursuit by Everton, the defender was finally secured on a five-year deal for an initial €30.25m (£27.2m) plus €1.5m in add-ons.
Mina only joined Barca in January from Brazilian side Palmeiras.
Gomes joined Barcelona from Valencia in 2016 for (£31.46) €35m but has struggled to nail down a starting place at the Nou Camp.
The 25-year-old joined Barcelona in a £42m deal in 2016, less than a fortnight after helping Portugal win the European Championship.