The 24-year-old, who can also operate at centre and full back, will add to the back line options and firepower at Cardiff Blues as he links up once again with Head Coach Danny Wilson.
The Swansea-born back is currently in his second spells at Scarlets, where he has amassed 322 points in 63 matches.
Shingler, capped for Wales at Under-20 level, joins Nick Williams, Matthew Morgan and Rhys Gill as Cardiff Blues continue to shape and build the squad for next season.
Head Coach Wilson said: "Steve is someone I have worked with in the past and I know what a quality player he is.
"His goal kicking and kicking in general play is very strong and he has a lot of experience from operating at fly half and centre in both the Guinness PRO12 and English Premiership.
"Steve is an excellent professional and a very good addition to the squad we are building here at Cardiff Blues."
Shingler made his competitive debut for Llanelli RFC in 2009 before making his Scarlets bow in pre-season and the LV=Cup in 2010.
Following a two-year spell in England with London Irish, Shingler returned to Scarlets and has been a key performer this season in both the Guinness PRO12 and European Rugby Champions Cup.
Shingler said: "I'm looking forward to linking up with Cardiff Blues from next season.
"Danny Wilson is assembling a great squad, recruiting strongly and I hope I can play my part and help the region achieve its long-term aspirations.
"I'm currently sidelined with a knee injury, but I'm looking forward to getting back and contributing towards the end of the season as the Scarlets push for a big finish in the league."
Factfile:
Full name: Steven Shingler
Born: June 20, 1991, Swansea, Wales
Major teams: Llanelli, Scarlets, London Irish
Position: Fly half/Centre/Full Back
Height: 6ft 3in
Weight: 88kg
Guinness PRO12 Blues News
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