Blackpool led the league in September after a fast start but plummeted down the table in a campaign that saw manager Paul Ince sacked in January.
Barry Ferguson's short-lived tenure as caretaker boss - which he later combined with a playing role - was marred by off-field incidents and Blackpool, who won just four of their last 30 league games of the campaign, only avoided relegation by two points.
But the appointment of the 56-year-old Riga is seen a positive step, with the Belgian guiding Charlton Athletic to Championship safety last term.
Charlton were in a perilous position when Riga took charge but he saw them win seven of their last 14 matches to finish seven points clear of the bottom three.
Coincidentally, Riga's last match in charge of Charlton was a 3-0 win at Blackpool on the final day of the season.
A statement released on Blackpool's official website read: "Blackpool can confirm the appointment of Jose Riga as the club's new manager.
"The former Standard Liege and Charlton Athletic boss, 56, has agreed a one-year rolling deal to take charge at Bloomfield Road.
"Born in Oupeye, Belgium, Riga has more than 20 years of experience in football management and coaching and becomes The Seasiders' first foreign boss."
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