Alomar's No. 12 will be the first uniform number retired in the Blue Jays' 35-year history during an on-field ceremony on July 31 at Rogers Centre.
"This is an honor that I was not expecting," Alomar said during a news conference on Tuesday evening at Rogers Centre. "I knew my numbers were worthy of consideration for the Hall of Fame, but for the Blue Jays to select my No. 12 to be the first number they retire is a great honor.
"I am truly blessed to be a Blue Jay and I'm looking forward to the ceremony on July 31."
Alomar played five seasons with the Blue Jays, including the World Series championship teams of 1992-93. He was named to the American League All-Star team and won a Gold Glove in each of his seasons with Toronto, from 1991-95.
The native of Puerto Rico's .307 career average as a Blue Jay is the highest mark in club history among those with a minimum of 2,000 plate appearances.
Alomar was elected to the Hall of Fame on Jan. 5, and will be enshrined in Cooperstown -- portrayed in a Blue Jays cap on his plaque -- in a ceremony on Sunday. The festivities can be seen live on MLB Network and MLB.com beginning at 11:30 a.m. ET.
A week later on Roberto Alomar Day, the first 20,000 fans entering the park for a 1:07 p.m. ET game against the Rangers will receive a collectible Alomar bobblehead on the day when his jersey number will also officially be retired.
"Roberto is a very special part of the Toronto Blue Jays organization and arguably the greatest second baseman of all-time," team president and chief executive officer Paul Beeston said. "His number deserves to be retired so that his contributions and excellence can stand as a model for all those who have the honor of wearing a Blue Jays uniform."
The No. 12 will now forever be a part of Blue Jays history. Alomar started his baseball career wearing No. 1, but always had a fondness for No. 2 because that was the number of his father -- and former Major Leaguer -- Sandy.
"I always wanted to be just like my dad," Alomar said. "No. 2 was my favourite, but when it came to a point when I had to decide to pick a number, I said I want No. 2 when they called me up to the San Diego Padres.
"I couldn't have it because my father was the coach. Then I asked for No. 1, and I couldn't have it because Gary Templeton was No. 1. So I said what about No. 12. That's how I became No. 12."
Alomar kept that number for nearly his entire 17-year career -- save for a brief stint with the Diamondbacks. During his career, Alomar recorded 2,724 hits, 210 home runs, 1,134 RBIs and 474 stolen bases.
He finished in the top six of the American League MVP Award voting five times and won a Major League-record 10 Gold Gloves at second base.
Now, Alomar is set to make history by becoming the first Toronto player to have his number retired. The only retired number the club currently observes is Jackie Robinson's No. 42, which was retired throughout Major League Baseball in 1997.
"It's special that the organization blessed me with this number first of all," Alomar said. "What else can I say? I should take that number home. When I was a little boy I never expected this to happen, especially because I only played here for five years.
"It was the five greatest years of my life and now that I'm being inducted into the Hall of Fame with the Blue Jays cap, I am really honored and proud. I didn't play the game to achieve that goal but I must have done something right."