Letters have gone out to all season ticket holders advising them of the changes. Still, many may be caught by surprise.
A video from the NFL puts it simply, "There's a new way for you to bring personal items into the stadium."
The changes will mean that items you've brought into stadiums for years will no long be permitted. Jim Mercurial oversees stadium security at Candlestick Park.
"I think what they looked at is the delivery protocols or delivery mechanisms for which those who are looking to harm folks, innocent folks, would deliver candidly explosives and things of that nature," said Mercurial.
The Boston Marathon bombing prompted the NFL to review its own security procedures. The league has come up with something they think will improve safety without causing huge back-ups at the stadium gates.
"The size and dimensions of the bag have changed. No more bags what so ever other than a small clutch purse for women for example. We have an approved NFL bag that has been distributed to all of our season ticket holders," said Mercurial.
Everything that can't fit into your pocket must be in a clear one gallon Ziplock bag or a clear tote bag that's no bigger than 12x12x6 inches. Purses larger than a typical hand will not be permitted. Neither will coolers, brief cases, backpacks, or even fanny packs.
Blankets must be carried in by hand and stadium seat cushions with zippers won't be allowed. The fear is something could be hidden inside the zipper. Seat cushions without zippers will be allowed.
Fans we talked to at Ricky's Sports Theater and Grill in San Leandro are grudgingly accepting the changes.
"It's a bit of an inconvenience. But as far as dealing with the world as it is right now, it seems to be a necessary situation," said Bob Ricardo, a Raider fan for 43 years.
"I think it's going to be a little hard to control. I can see a lot of people getting upset. But you know, you got to do what's right for everybody," said San Leandro resident John Warter.
Teams want to thank everyone for their patience in advance.
"We know that there's going to be some hick ups, we know that it's going to look a little different. It's going to feel a little different," said Mercurial.
The 49ers sent out one free bag to each season ticket account holder. Raider season ticket holders received one free bag for ever two seats purchased. Additional bags are available for just $5 at concession stands, team stores and NFL websites.
The regulations are posted here.