Navarro was selected by American League manager Terry Francona of the Red Sox, while Kazmir was selected by the players' ballot.
Rays rookie third baseman Longoria won the Final Vote for the AL, beating out the White Sox Jermain Dye.
"I'm just happy there's more than one," Kazmir said. "There's a lot of players in here who deserve to be on the team."
J.P. Howell is one Rays player who was a candidate to make the team but did not.
"I'm always disappointed every year, wherever I'm at, but I think the two guys going are great representatives for us and they deserve to be going," Howell said.
The 79th Major League Baseball All-Star Game will be televised nationally by FOX, in Canada by Rogers Sportsnet and Sportsnet HD and televised around the world by Major League Baseball International, with pregame ceremonies beginning at 8 p.m. ET. ESPN Radio will provide exclusive national radio coverage, while MLB.com will provide extensive online coverage. XM will provide satellite radio play-by-play coverage of the XM All-Star Futures Game.
Navarro, 24, will be on his first All-Star team.
"I was surprised I made the All-Star team, but not surprised since everybody has been asking me about it the last couple of weeks," Navarro said.
Navarro has experienced a huge turnaround from 2007, when he hit just .177 with one home run and 13 RBIs before the All-Star break. This year, though, he's shone on offense and defense.
"I think I wasn't happy when I was going through my struggles," Navarro said. "But I've learned so much about me through that and what I'm capable of doing. ... [Making the team] is really special for me."
Through Sunday, Navarro is hitting .318 with four home runs and 33 RBIs, including an on-base percentage of .370 and a slugging percentage of .435. His average has not been below .300 all season.
"I think his whole thing has been his working out in the offseason," Rays pitcher James Shields said. "His approach to starting this season was a lot different than the last couple of years. I think it's shown. It's been a big difference, not only in his physical game, but his mental game. Being a catcher you have to be mentally tough. I think that offseason was good for that."
Behind the plate, Navarro has been outstanding, committing just one error thus far. He has started 58 games this season, including 56 of 67 since returning from the disabled list on April 22. He suffered a freak accident in April, slicing two fingers in the dugout netting after slipping down the steps in the visiting dugout in Yankee Stadium.
For Kazmir, this will be his second stint on the AL All-Star team, as he becomes the Rays' second two-time All-Star (Carl Crawford, 2004, '07). The 24-year-old left-hander made the team in 2006 and pitched one shutout inning, allowing no hits.
Making the team was nice for Kazmir, but how he did so made the honor more significant.
"That was the big thing, to know that your peers really respect your game," Kazmir said. "To vote you in, that means the most to me."
Kazmir missed the first month this season while recovering from soreness in his left elbow. After dropping his first start of the season to the Red Sox, he won a club-record six consecutive starts.
He becomes just the third pitcher to be selected to the All-Star team after missing April with an injury; Charlie Hough (Texas, 1986) and Ewell Blackwell (Cincinnati, 1949) are the other two.
Kazmir is 7-3 with a 2.63 ERA in 12 starts, including 75 strikeouts in 72 innings.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.