Are Apple Notes locked notes secure?
Apple Notes is free, syncs everywhere, and can lock individual notes. So is it enough? Mostly yes, with two gaps worth understanding.

Apple Notes is good — within limits worth knowing.
Short answer: Apple Notes is a solid, well-built app, and its locked notes feature really is end-to-end encrypted — Apple cannot read a note you have locked. For most everyday writing that is plenty. The nuance is in what "locked" covers and what your regular, unlocked notes get.
By default, your ordinary notes sync to iCloud with encryption in transit and on Apple’s servers, but with keys Apple holds — unless you have switched on Advanced Data Protection. That means, in the standard setup, Apple (and anyone who legally compels Apple) can access unlocked notes. Locked notes are the exception: they are end-to-end encrypted regardless.
The honest summary
- Locked notes in Apple Notes are end-to-end encrypted — genuinely private.
- Unlocked notes are not end-to-end encrypted unless you enable Advanced Data Protection.
- You cannot lock notes that contain certain attachments, like PDFs or scanned documents.
- For a handful of secrets, locking works; for a whole vault of sensitive material, a dedicated app is cleaner.
What "locked" does and does not cover
When you lock a note, its contents are encrypted with a key tied to your passcode or password, and Apple keeps no readable copy. That is the real deal. But the feature is per-note and a little fiddly: you have to remember to lock each sensitive note, the title stays visible in the list, and notes with some attachment types simply cannot be locked at all. It is protection you have to apply by hand, every time.
Advanced Data Protection changes the maths
Apple’s Advanced Data Protection extends end-to-end encryption to far more of your iCloud data, including all Notes. If you turn it on, your unlocked notes become end-to-end encrypted too. The catch: it is off by default, it requires you to set up account recovery contacts or a key, and it covers iCloud, not the broader question of an app that simply never uploads.
If you are weighing notes apps generally, our encrypted notes ranking lays out where Apple Notes sits against dedicated options, and the scorecard there shows the trade-offs at a glance.
So, is it enough for you?
For a few private notes among many ordinary ones, Apple Notes with locking is genuinely fine, and turning on Advanced Data Protection makes the whole app much stronger. Where it stops being the right tool is when "sensitive" describes most of what you write, when you want one passphrase to cover everything, or when you would rather your notes never touch a cloud you do not control. At that point a dedicated, local-only encrypted app is the simpler, safer answer.
Apple Notes security, answered
Can Apple read my notes?+
Apple cannot read notes you have locked, and cannot read any notes if you have enabled Advanced Data Protection. In the default setup, your unlocked notes are encrypted with keys Apple holds, so they can be accessed by Apple or via legal compulsion.
Are locked notes safe if I lose my phone?+
Yes — a locked note stays encrypted, so a thief who gets your phone still cannot read it without your passcode or note password. This is exactly the kind of "at rest" protection a good encrypted notes app provides for everything.
Should I use Apple Notes or a dedicated app?+
Use Apple Notes for convenience and the occasional locked note, especially with Advanced Data Protection on. Choose a dedicated local-only app when most of your notes are sensitive and you want everything encrypted by default without per-note steps.