The Manchester City player and Daniel Carvajal did not make the final 23-man squad for the tournament in Brazil but wished their team-mates the best of luck
Navas missed out on a spot in the squad with the coach concerned about his fitness after he recovered from an ankle injury.
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"I'm proud to have recovered in time and to have fought for a spot in Brazil," Navas wrote on Twitter.
"I wish my team-mates and the boss luck in retaining the title."
Real Madrid defender Carvajal was another to be cut from the star-studded 30-man squad as Spain aim for a fourth straight major tournament win.
The 22-year-old tweeted: "It's a shame I didn't get into the final list, but I'm so proud to have been close. Best of luck to Spain."
Meanwhile, Atletico Madrid midfielder Koke was delighted to have been selected for his first World Cup after a good campaign for the La Liga champions.
"So happy to be picked for Brazil! I'm very keen to help the team at my first World Cup."