There are several platforms where you can obtain free subdomains. One of the most popular services is Freenom, which provides free domain registration that includes subdomains. Another well-known platform is WordPress.com, which offers free subdomains as part of its free plan, allowing users to host their blogs or websites under a WordPress-branded domain.

GitHub Pages also allows you to host websites for free with a subdomain of github.io, particularly beneficial for personal or project sites. You might also consider platforms like Wix and Weebly, which provide free subdomains for their website builder services.

Additionally, some hosting services or domain registrars might offer free subdomains as part of their promotional deals or trial periods. It’s advisable to check their official websites for the most current offers and terms of service. Always ensure you read and understand any limitations or terms associated with using these free services, such as bandwidth restrictions or display advertising.