This is a return to rugby sponsorship for the online betting company, following its title sponsorship of the Middlesex Sevens earlier this month.
The deal involves branding on the reverse of all the Guinness Premiership clubs' playing shirts on the number patch.
Dominic Harrison, e-commerce managing director of , said: "This sponsorship is truly exciting for us as it is the first time we have become involved with a sport outside our traditional racing environment for some time.
"The sport of rugby union has real momentum about it at present and we are looking forward to contributing to that especially at club level. We intend to be pro-active and get involved with clubs and their supporters across the season."
Twelve Guinness Premiership clubs will receive donations from Coral.co.uk through a "bounce back" scheme, which directly rewards clubs when their supporters open an account with Coral. Clubs can also raise money for their development programmes through a "celebrity supporter betting challenge".
Matt Dawson, the former London Wasps, Northampton Saints and England scrum half, will play a key role in the sponsorship. He has signed as the Coral.co.uk ambassador and will host a number of poker nights for club supporters around the country.
A new has also been created where players can explore a database of 10 years of professional rugby information as well as the latest betting information.
Earlier this week, Coral, which currently sponsors the Racing UK channel, announced plans to increase sports sponsorship presence following competition from other online gaming sites.
Middlesbrough, Aston Villa, Tottenham Hotspur, Blackburn Rovers and Leeds United football clubs have signed shirt sponsorship deals with online gaming companies, while Betfair is involved in cricket sponsorship.
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