The fourth suspect is expected to surrender on Monday.
The crew is tied to thefts from more than 20 stores, and police say they got away with merchandise worth more than $15,000.
The name comes from one of the main items they stole.
They mainly targeted Family Dollars, Dollar Generals, and Rite Aids all over Philadelphia.
However, they were concentrating on two specific neighborhoods: Juniata Park and Fox Chase. The Dollar General on the 1200 block of East Erie Avenue was hit several times.
They walk in hiding large pillowcases, laundry bags or trash bags. Then they fill them up with diapers, batteries and coffee.
Police say the suspected ring leader is Daquan Johnson, who is being held on $250,000 bail. Byron Jordan-Prince and Lytrell Scott were also arrested.
"We know this crew was stealing diapers because there's a value to them, and they were selling them to a third party. So it affects not only the store, the neighborhood, but its jobs too," said Inspector Ray Evers.
Police credit the work done in conjunction with the district attorney's office to crack down on retail thefts.
Investigators say there has been an 81 percent increase in arrests over this time last year.
"The number of arrests and prosecutions are up but we're not finished. We think there are people out there who have gotten used to this type of thing during the pandemic," said First Assistant District Attorney Robert Listenbee.
Police also credit an app they are using to communicate with around 1,800 retailers in the city to catch suspected thieves.