Open Instagram and tap Forgot password? or Get help logging in
Enter the phone number linked to the account
Check the SMS code sent to that number
Use the code to access the account or view the connected username
Search the phone number in your phone contacts and sync contacts in Instagram
Open the profile suggestions from synced contacts to find the matching Instagram account
Use the phone number in Instagram’s search bar only if the account is publicly discoverable
Check mutual contacts or shared groups for the username
Use a trusted people-search or reverse lookup service if you have legal permission
Contact the person directly and ask for their Instagram ID
Respect privacy laws and Instagram’s terms of service