What each one does
Both a freeze and a lock stop lenders from seeing your credit report, which blocks new accounts from being opened in your name — the main way identity thieves hurt you.
Neither lowers your score, and neither touches accounts you already have. Your existing cards and loans keep working normally.
The freeze: free and federally backed
A security freeze is guaranteed free by federal law at all three bureaus. You place it (and lift it) through each bureau, and they must act within one business day when you ask online.
It's the strongest, cheapest protection — the trade-off is that you lift it yourself each time you apply for new credit.
The lock: faster, often paid
A credit lock does the same job but is a product the bureau offers, often through an app, with instant on/off. Some locks are free; others come bundled with a paid monitoring subscription.
Locks are governed by the bureau's terms rather than federal law, so read what you're agreeing to before you rely on one.
Which should you use?
For most people, the free freeze is the right default — full legal protection at no cost. Choose a lock only if you value the instant toggle and don't mind the terms or fee.
Whichever you pick, you can still check your own reports, and a freeze or lock never stops you from disputing errors for free.
A freeze and a lock both shut the door on new-account fraud; the freeze is free and backed by law, the lock trades a fee or subscription for speed. Subefy explains your options in your language and reminds you when to lift protection before you apply. Credit disputes are always free.