Tell AT&T Park goodbye, Giants fans.

Buster Posey, Brandon Crawford and their mates henceforth will play ball at Oracle Park.

The Giants on Thursday will announce a 20-year agreement with the Redwood City technology company to affix its name to their waterfront ballpark in San Francisco.

Terms of the deal are not being disclosed, but in an interview Wednesday, Giants President and CEO Larry Baer termed it “very much in line with other recent naming-rights deals for top-tier facilities.”

That could make it worth $300 million to $350 million, a significant increase over the roughly $100 million the Giants received over 23 years in the original naming-rights and marketing deal that they signed with an AT&T predecessor in 1996.

The change is effective immediately. The AT&T signs that were installed in 2006 are being removed, to be replaced Thursday with temporary Oracle Park banners.

Under the agreement, the Giants get substantially more revenue and a name tied to a well-known Silicon Valley tech giant. Oracle gets to place its name on another Bay Area sports venue now that the Warriors are moving to the new Chase Center in San Francisco, and the arena in Oakland will be renamed.

As for Giants fans, they must get accustomed to a fourth name for the ballpark since it opened as Pacific Bell Park in 2000.

This change will be harder to accept for some fans because they celebrated three World Series championships, an All-Star Game and the Barry Bonds’ record-setting 756th home run at a park they knew as AT&T.

But that’s the nature of sports marketing.

AT&T’s naming rights were to end after the 2019 season, but during their exclusive window to renegotiate during the final quarter of 2018 they told the Giants they were going in a different strategic direction, Baer said.

AT&T gave the Giants the option of ending their deal a year early if the team could find a new partner in short order. The Giants called about a half-dozen of their marketing partners to gauge interest, Baer said, and Oracle jumped in.

“The organizations know one another well,” Baer said. “That’s the only way we were able to get a deal this quickly. It was hatched over the holidays.

“It’s an iconic park, and we kind of view it as a landmark. We said early on we want this park to age gracefully to the point we can feel like what Fenway might feel like in Boston, and Wrigley might feel in Chicago.

“Nobody knows this park, other than AT&T, better than Oracle.”

Oracle CEO Mark Hurd said making this investment was a no-brainer, given a long-standing partnership with the Giants and the visibility it gained by the Warriors’ three NBA championships over the past four years while playing at Oracle Arena.

Hurd said there was “no question” their experience at the Oakland venue played a part in their decision to deal with the Giants.

Oracle has sponsored the suite level at China Basin since 2003 and conducted other business with the Giants. Most notable, Oracle holds a concert at the ballpark during its annual OpenWorld conference every fall.

During the 2011 conference, the Giants presented Oracle founder and Chairman Larry Ellison with a World Series championship ring.

“There’s been a lot of trust built up between the two organizations over the years,” Hurd said. “We think there’s some really exciting things we can do with the park going forward, innovative things we can do to help both the fan experience and community.”

Part of that is using Oracle’s technological know-how to boost automation and information delivery at the ballpark, which will be named for a Bay Area company for the first time in more than 15 years.

The Giants sold the original naming rights to now-defunct Pacific Telesis in 1996, four years before the stadium opened. The San Francisco-based “Baby Bell” agreed to pay about $50 million over 24 years, including $23 million up front to help build the park.

The name was changed to SBC Park in 2003 after the Texas-based firm bought Pacific Telesis, and then to AT&T Park three years later when SBC bought AT&T and adopted the more recognizable name. AT&T is based in Dallas.

The original naming-rights deal was amended amid the name changes, and with an expanded marketing partnership, it grew to more than $100 million, averaging about $5 million a year. But over two decades the annual fee fell far below the going rate.

In 2013, AT&T paid a reported $17 million to $19 million a year to affix its name to the palatial new Cowboys stadium in Arlington, Texas.

Oracle, founded in 1977, is a $40 billion business software company that has 137,000 employees.

“We really like the fact that Oracle is a local company,” Baer said. “They’re not going anywhere. We’re not going anywhere. Having a Bay Area-based company with the naming rights was a consideration.”

Henry Schulman is a San Francisco Chronicle staff writer. Email: hschulman@sfchronicle.com Twitter: @hankschulman