Marine experts say they are delighted that a school of bottlenose dolphins has been spotted in the river Wear.
The sightings come after one dolphin, nicknamed Andy, became a regular visitor to the estuary.
Now several of the marine mammals have been seen chasing fish into the mouth of the river.
Experts say the arrival of the dolphins is a testament to the cleanliness of the sea and rivers around the Sunderland coast.
Sandra Dobigny, community wild space officer said: "It's exciting to see the dolphins stop off at Sunderland on their annual migration south.
"The city's countryside team manages coastal sites to protect wildlife across Wearside and it's a great reward to see the dolphins amongst the species they attract."
Councillor Mel Speding, cabinet member with responsibility for culture, arts, sports and leisure at Sunderland Council said: "People travel all over the world to see these beautiful creatures and here they are off the Wearside coast.
"We should all work together to protect nature and the environment, and make sure they return again and again to make their occasional home amongst our local wildlife."
Both Seaburn and Roker beaches boast a European Blue Flag, given to areas with high standards of bathing water.