If you are on a personal phone or tablet:

Proxy servers act as intermediaries between your device and the internet. You can use a proxy server to access AO3 by entering the proxy server's URL and AO3's URL in the proxy server's search bar. Keep in mind that proxy servers may have limitations and security concerns.

Be wary of "mirror" sites claiming to be AO3. Stick to the official domain whenever possible to protect your login credentials. Conclusion