On 28 May at around 4.05pm the victim left a DLR train at Blackwall station with a friend.
As they turned to go down the stairs, the victim was sexually assaulted by a man.
He then walked past her down the stairs.
Officers believe the man in the CCTV images may have information that could help their investigation.
If you recognise him or have any information please contact BTP by texting 61016 or calling 0800 40 50 40 quoting reference 398 of 28/05/21.
Alternatively, you can call Crimestoppers anonymously on 0800 555 111.