Quick note first, because this search means two things. If you want to install TikTok, it is in the App Store, and that is the whole story. This page is about the other one: keeping a video from TikTok on your iPhone.
Why not just use the app's save button
You can, and for a quick keepsake it is fine. But TikTok does not hand you the file it was playing.
It rebuilds the clip as you save and burns a moving watermark into the picture, with its logo and the creator's name. That rebuild is also a second round of squeezing, on top of the one the video already went through when it was posted.
So you end up with a softer picture and a stamp that cannot be cropped out, because it moves across the frame on purpose.
Download a TikTok on iPhone in 3 steps
Copy the link in the TikTok app
Tap Share, then Copy link. You get a short vm.tiktok.com address.
Open the downloader in Safari
Paste the link into the field. The short address is followed for you.
Tap download, and accept the prompt
The first time, Safari asks whether you allow downloads from the site. That is normal browser behaviour, not a problem with the page.
Download on your iPhone
Works in Safari. Nothing to install, no account.
Open the downloaderWhere the file actually goes
Not to your camera roll. This is the part that catches everyone out.
Safari saves to the Files app, in a Downloads folder. You can get to it straight away by tapping the download arrow that appears next to the address bar. (Apple Support)
The video is on your phone at that point. It is simply not in Photos yet.
Moving it to Photos
Open Files
Go to On My iPhone → Downloads. Your video is there, named after whatever the site called it.
Long-press the file
Then tap Share in the menu that appears.
Choose Save Video
It now appears in your camera roll, in with everything you filmed yourself.
In Files, tap Select, tick every video, then Share → Save Videos. Much faster than one at a time if you have been collecting clips for an edit.
Why iOS works this way
It is worth understanding, because it stops it feeling like a bug.
Your Photos library is a protected space on iPhone. Only apps you have explicitly allowed can write to it. Safari does not get that permission by default, so a browser download lands in the file system instead.
Android does the opposite: files go to Downloads and the system scans them into your gallery on its own. Neither is wrong. Apple simply chose to keep the photo library closed.
Keeping Safari open
One iPhone quirk worth knowing. If you switch to another app in the middle of a download, iOS may pause it to save battery.
For a short TikTok that finishes in a second, it never comes up. For a long video, leave Safari on screen until the arrow stops moving.
If the video will not download
Three things cover almost all of it.
You copied a profile link. Easy to do, because the buttons sit close together. A video link contains /video/ or is a short vm.tiktok.com address. A profile link stops at the username.
The video was taken down, or the account went private. Open the link in a private tab: if TikTok will not play it there either, it is gone.
The link came through several apps. A link forwarded through a few chats often arrives wrapped in extra bits. Copy it fresh from TikTok.
Watch your storage
TikTok clips are small on their own, but they add up fast when you are saving dozens for an edit. A hundred one-minute clips in 1080p is roughly a gigabyte.
Files makes this easy to manage. Everything sits in one Downloads folder, so you can clear it in one go once the videos are safely in Photos or on your computer.