Dial 199 from your BSNL SIM and ask customer care for your number
Dial 1503 and check your SIM details through IVR or customer support
Use the USSD code *1# from your BSNL SIM
Send an SMS with the text BAL to 123 to check SIM-related details if supported
Check the SIM pack, welcome letter, or SIM card holder for the printed number
Open your phone settings and check under SIM status or About phone
Call or send a message to another phone and see the number displayed there
Use the BSNL Selfcare app if your number is already linked to the app
Visit the nearest BSNL customer service center with valid ID proof
Ask a friend or family member to note the number when you call or message them