T-Mobile has finalised a 25-year deal to become the new naming rights partner of the home ballpark of Major League Baseball (MLB) franchise the Seattle Mariners, with the telco set to focus on ramping up the fan experience at the stadium.

The partnership, subject to approval by the Washington State Major League Baseball Stadium Public Facilities District (PFD), was first reported last month and on January 1 the ballpark will be rebranded as T-Mobile Park through to 2043. Financial terms of the deal were not disclosed, but MLB.com reported that it will be worth around $3.5m (£2.75m/€3.05m) per year.

Insurance company Safeco has held naming rights throughout the life of the stadium, but announced last year that it would not seek to extend its 20-year contract, which is due to expire on December 31. The T-Mobile deal was expected to be confirmed after the Mariners sealed a new lease agreement for the ballpark earlier this month with the Public Facilities District (PFD), the body that oversees the stadium.

The agreement obligates the Mariners to pay a minimum of $600m for ballpark maintenance, operations, capital upgrades and fan improvements over the next 25 years. Under the T-Mobile deal, all fans will be able to get early access to the ballpark on game days via the T-Mobile ‘Pen.

This gathering place for fans spans from the bullpens behind Left Field to Center Field. Opening 30 minutes before all other gates, the T-Mobile ‘Pen gives fans the chance to watch Mariners batting practice and pitcher warm ups. T-Mobile ‘Pen will feature a variety of new perks including surprise giveaways and a live DJ on select game days, to go with destination food and beverage offerings.

T-Mobile will also provide Mariners fans with surprise seat upgrades, and free stuff at Tuesday games under the ‘T-Mobile Tuesdays’ banner. T-Mobile customers will get some extra perks including fast-track entry, discounted tickets and exclusive offers on merchandise.

John Legere, T-Mobile CEO, said: “T-Mobile Park isn’t just some corporate-branded sponsorship to us…this is about supporting the community and our hometown Mariners in building a World Series-calibre team.”

Mariners president and CEO, Kevin Mather, added: “Fans have come to expect a great experience at this ballpark and we have made a commitment to invest substantial club revenues over the next 25-years to make sure that continues. This partnership with T-Mobile will help us meet that obligation so that fans will have a first-class experience at T-Mobile Park for decades to come.”

At the end of the new lease agreement, the total investment of Mariners revenues into the publicly owned ballpark since 1999 will add up to over $1bn. The process of incorporating the T-Mobile branding assets throughout the ballpark will take place over the coming months. Much of it is expected to be completed by opening day on March 28, 2019, when the Mariners meet the Boston Red Sox.