Bloomquist is expected to compete for the Royals' second-base job with Alberto Callaspo, who finished last season as the regular at that spot.
"He'll create competition on the field, which is a good thing," said Royals general manager Dayton Moore.
A right-handed batter, Bloomquist, 31, played seven years with the Seattle Mariners. He had a .263 average in 540 games and played every position in the infield and outfield.
The deal, reported earlier by MLB.com, was announced late Friday afternoon after Bloomquist passed a physical examination in Kansas City. His contract was believed to be worth about $3 million for the two years.
"We're excited to get him," said Royals manager Trey Hillman. "Not only the versatility, but also the speed that he adds. He's a well-above-average runner and he gives us, depending on how things shake out in Spring Training, another added element because he might be in our lineup."
Bloomquist doesn't have much power -- just six homers in his career -- but has 71 stolen bases in 87 attempts. His on-base percentage is .322 for his career, including .377 last season when he batted .279.
"He's an on-base guy, a speed-type player and a hustler," Moore said. "He's a Craig Counsell-type who really plays hard, hustles and knows how to play."
Bloomquist is considered an "igniter" who is also well regarded for his leadership abilities in the clubhouse. Hillman talked at length with him on Thursday.
"The reports are off the charts on character and team play and fire for the right reasons. That definitely came through in the conversation. He's hungry; he's excited," Hillman said.
This signing apparently will satisfy the Royals' quest for a seasoned middle infielder to supplement shortstop Mike Aviles, who was the Royals Player of the Year in his rookie season.
Earlier this offseason, the Royals were a late entry in the pursuit of shortstop Rafael Furcal, who signed with the Los Angeles Dodgers. There were hints that the Royals might have interest in second baseman Orlando Hudson, but nothing ever developed there. Recently there was a report that David Eckstein, who can play either side of the infield, interested the Royalss but that wasn't the case.
Bloomquist, in his 460 Major League games, has played 86 games at second base, and Moore considers second and center field as his best positions.
"He's never really been an everyday player, but he's always had good people ahead of him like [center fielder Mike] Cameron, [shortstop Yuniesky] Betancourt and [second baseman] Jose Lopez," Moore said.
Bloomquist also has played 125 games in the outfield, 111 at shortstop, 107 at third base and 31 at first base. His overall fielding percentage is .977 with 27 errors, eight at second base.
"He's a winner, he has versatility and he's a very good offensive player," Moore said.
Unless there are other moves, the Royals now have Bloomquist, Callaspo and Esteban German as potential second basemen and Aviles, Tony Pena Jr. and Mario Lisson as shortstops on the 40-man roster.
It's possible that a platoon arrangement might develop for Bloomquist and Callaspo. However, Callaspo, a switch-hitter, in his career actually has a better average against left-handers (.295) than right-handers (.253).
Callaspo batted .305 last year, with his season interrupted by a stay on the disabled list. He's having another good winter in the Venezuelan League with a .303 mark in 54 games for Aguilas de Zulia.
Last season, Bloomquist's .279 average and .377 OBP were the best of his career except for his spectacular break-in stint during a September call up by the Mariners in 2002. He went 15-for-33 (.455), in 12 games. That same season he was the Triple-A Tacoma Rainiers' Most Valuable Player.
Bloomquist spent the next six seasons with Seattle, forging a useful presence as a utility player. The most games he played in a season was 102, in 2006. Appearing at every position except pitcher and catcher, he made a career-low two errors and ranked second on the club only to Ichiro Suzuki with 16 stolen bases.
Bloomquist has never had more than two home runs in a season, and one of his six was an inside-the-parker at Houston in 2007.
"He'll help our team speed," said Moore.
The Royals lost speed when Joey Gathright, who had 21 steals last year, was not offered a contract and signed with the Chicago Cubs.
This is the third deal by Moore this offseason that could result in a new face at a regular position. He traded to acquire first baseman Mike Jacobs from the Florida Marlins and then obtained center fielder Coco Crisp from the Boston Red Sox.
Bloomquist fills the Royals' winter roster at 40 players.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.