Pet shop chain Pets at Home has opened at the Cantium Retail Park in Old Kent Road.
The store, which opened on Friday, occupies the former premises of electrical chain Comet alongside B&Q and Halfords.
30 children from St Francis Primary School in Peckham were the first to meet the store's small animals, fish and reptiles.
St Francis is well-known as the patron saint of animals.
The store team also treated the children to a series of pet care workshops, a chance to learn more about what pets eat, where they sleep and their healthcare needs.
Laura Cumming, winner of a recent competition on the SE1 website, also took part in the opening celebrations to collect vouchers for her dog Albert.
"What a fantastic start!" said store manager Nick Briscoe.
"Our opening weekend went even better than we had hoped and it was great to welcome St Francis Primary School."
Pets at Home on Old Kent Road also hosts an adoption centre where pets such as rabbits, guinea pigs, hamsters and other small animals are cared for until a new loving home can be found.
Other features include a pet village, aquatics centre, reptile centre and a groom room.