Contents

Open app → Messages (Direct). Delete one by one: open chat → long press message → Delete. No bulk delete for all chats in Instagram — manually or third-party tools (be careful with access).
Reasons and ways to delete
Reasons: privacy, profile look, cleanup. Ways: delete each message manually, third-party apps (risk), create a new account.
Step-by-step
Messages → select chat → open thread → hold message → Delete. For whole chat — options in dialog header if available.
Video:
FAQ:
Do messages delete only in the selected chat?
Yes. Deleting in one chat doesn't affect others. The other person may still have the thread.
Can I restore deleted messages?
No. After deletion they can't be restored in Instagram. Save important ones first.
Will messages disappear for the other person?
No. Deletion is only on your side. They still see the conversation.
Is there a way to delete all messages at once?
Not in the Instagram app. Only one by one or per chat. Third-party services are not recommended for security.