Nathan Karns (3-1) gave up three runs over six-plus innings. Seattle's right-hander lost to Oakland in his first start of the season on April 9 but struck out six and walked one this time to earn his third straight win.
Khris Davis homered twice and had three RBI for the A's.
All of Seattle's runs came off starter Kendall Graveman (1-3), who has been tagged for 10 runs over his last 11 innings.
The Mariners did most of their scoring on a pair of two-out hits in the sixth.
Seager doubled in Cano one batter after Lind hit into double play, and Iannetta followed with an RBI single to put Seattle up 3-1.
Nori Aoki doubled in the seventh, stole third and scored on a throwing error.
Karns and four relievers made it hold up with some help from Seattle's defense, which turned a pair of double plays on line drives.
Davis homered leading off the second and added a towering, two-run shot in the seventh -- his fourth homer in nine games after hitting only one in his first 16 games.
Graveman struck out six and walked one in 6 1/3 innings.
Cano's double in the fourth put him in elite company. He became the fifth second baseman in major league history to have at least 2,000 hits, 450 doubles, 200 home runs and 1,000 RBI. The other four are Rogers Hornsby, Roberto Alomar, Jeff Kent and Craig Biggio.
The A's and Mariners each plan to have a representative at Tim Lincecum's showcase workout in Arizona next week. The two-time NL Cy Young Award winner is a free agent who hasn't pitched in the majors since June 27 but is hoping to return to the big leagues. "I'd be surprised if most teams weren't out there looking at him," Oakland manager Bob Melvin said. "He's been a big-time pitcher and a guy that is very well-liked out here in the Bay Area."
Mariners: RHP Joaquin Benoit (shoulder inflammation) could begin throwing by the end of the week. Benoit is eligible to come off the disabled list Friday.
Athletics: Lowrie was kept out of the starting lineup due to lingering soreness in his calf. . Mark Canha made his first career start at third base, with Chris Coghlan moving to second. Coghlan has been Oakland's primary third baseman since Danny Valencia went out with a strained hamstring. Valencia is eligible to come off the disabled list Friday.
Mariners: RHP Hisashi Iwakuma (0-3) starts against Oakland on Tuesday night seeking his third consecutive win over the A's.
Athletics: RHP Sonny Gray (3-2) has beaten the Mariners four times in nine career starts but did not pitch against them when the teams played in early April.