- Go to your applications folder
- Click on the Utilities folder
- Click on the “Keychain Access” App
- On the left-hand side, highlight the “System” keychain
- Select “Passwords” under the category
- Double-click on the Airport network password you want to remember
- Select the “Show password” checkbox
- Enter your administrator username and password (you may have to do this twice)
- See the password in the “show password” field.
Mac OS-X Showing Existing Wifi Passwords in Keychain – Composite Code.