Open Instagram
Tap your profile picture
Tap the menu icon
Tap Settings and privacy
Tap Accessibility and translations or App and media, if shown
Tap Dark mode or Theme
Select Dark
If no in-app option appears, enable dark mode in your phone’s system settings
On iPhone, go to Settings, then Display & Brightness, then Dark
On Android, go to Settings, then Display, then Dark theme
Reopen Instagram if needed