The deal is expected to be finalized later this month.
According to terms of the deal, $10 million will be used to upgrade the stadium, including the installation of HD video boards, "ribbon boards" and the updating of control room equipment. Those improvements will be completed by Opening Day next season.
"After much diligence and cooperation from both parties, we are delighted to make this announcement today," A's owner Lew Wolff said. "We believe this agreement works well for the city and county taxpayers, the team, A's fans and all involved. It provides stability for the A's while also improving fan and player experience with significant upgrades and improvements at the facility."
A report in the San Francisco Chronicle on Wednesday outlined the terms of the new lease. The deal includes gradual decreases in annual lease payments, as well as a promise to address sewage and blackout problems that have turned the Coliseum into the butt of jokes.
The A's will be responsible for making lease payments if they leave Oakland for another venue. If the team moves to a new stadium in Oakland, however, it would not have to make those payments.