Is using temp mail legal?

Yes — using a disposable email address is legal in most places for ordinary purposes: signing up for a service, downloading a resource, starting a trial, protecting your inbox from marketing mail. Email providers aren't restricted to government-issued identities, and disposable providers are a normal part of the email ecosystem.

Where it crosses the line

• Fraud and impersonation — using throwaway addresses to deceive people or transact illegally is illegal regardless of the inbox.
• Ban evasion — returning to services that banned you can violate their terms and, in some jurisdictions, computer-misuse laws.
• Trial and promotion abuse at scale — farming one-time offers with armies of addresses breaches the affected services' terms.
• Spam and malware — sending unsolicited bulk mail or distributing harmful content through any address is prohibited everywhere that matters.

The terms-of-service layer

Separately from law, a service can set its own rules: many forbid disposable addresses outright (see why sites block temp mail) and may suspend accounts that use them. That's a contract matter, not a criminal one — the practical takeaway is to respect a site's stated rules for accounts you care about.

Our own acceptable-use policy draws the same line: protecting your inbox is fine; abusing other people's services isn't.