Williams, victor of 23 Grand Slam titles during her career and a seven-time women's singles champ at the All England Club, took maternity leave for the birth of her first child.
It means the 36-year-old American, victor in 2016 but absent last year because of her pregnancy, will avoid the big names until at least the third round.
She will be seeded at Wimbledon only one place lower than Maria Sharapova, who she had been due to play in the fourth round at Roland Garros when she withdrew with a pectoral injury. The All England Club usually follows the latest ranking list but can make a change if deemed "necessary to produce a balanced draw".
By doing so, Williams has been afforded protection from having to face any other seeded player in either of the first two rounds. This comes on the heels of the six-time Wimbledon champion successfully campaigning for seeding lenience from the U.S. Open due to pregnancy-related absences.
Putting Williams at No. 25 now means that she could face someone seeded No. 1 through No. 8 in the third round. The draw will be selected Friday, and the tournament starts Monday.
Former world number one Serena Williams returns to Wimbledon after missing last year's tournament, while reigning champion Garbine Muguruza bids to retain the Venus Rosewater Dish.
Defending champion Roger Federer tops the men's seeds despite Spaniard Rafael Nadal knocking him off the top spot in the rankings this week.
The world number one arrives in London with serious momentum after finally winning her first Grand Slam crown.
The change puts Dominika Cibulkova, who had been ranked 32nd, into the open draw.
The Slovakia's didn't agree with organizers' decision to give a seed to Serena.
"I don't think it's the right thing to do", Cibulkova, a two-time Wimbledon quarterfinalist, told the BBC ahead of the announcement.
"But it's just not fair if there is a player [who misses out] and it's me now".
Wimbledon organisers have been accused of being set in their ways many times over the years, but the All England Club's seedings committee opted to break with the norm by promoting Williams.