Pledgely
Safari is where most porn on an iPhone gets watched, so it's the right place to start blocking. Apple gives you real tools for it. What Apple can't give you is a reason not to undo them, so this guide covers both halves: the blocking, and the loophole.
The four ways to block porn in Safari
1. Limit Adult Websites
The built-in option: Settings → Screen Time → Content & Privacy Restrictions → Content Restrictions → Web Content → Limit Adult Websites. Safari starts filtering adult sites, and Private Browsing disappears from Safari entirely while the restriction is on, which closes the classic "just go incognito" move.
Good: free, native, also applies to most third-party browsers. Bad: the filter misses plenty of newer sites, and your own passcode switches it off in under a minute. If it's already let you down, here's why that happens.
2. Never Allow lists
Under the same Web Content screen you can add specific sites to Never Allow. Useful for the handful of sites you always drift back to.
Bad: manual blocklists are whack-a-mole. There are always more sites than you can type, and the list is editable by you.
3. Locked SafeSearch
Force SafeSearch on Google and Bing so explicit results stop appearing in searches. Combine with the adult filter above for search plus site coverage. Setup: how to lock SafeSearch.
Bad: filters search results, not the sites themselves.
4. DNS filtering
Point the phone at a family-filter DNS resolver and adult domains stop resolving for Safari and everything else. It's covered in more detail in how to block porn on iPhone.
Bad: ten seconds to set, ten seconds to unset.
The loophole all four share
Every method above is administered by the person it's supposed to stop. That works when someone else holds the Screen Time passcode. When both people are you, the 2am version of you inherits full admin rights from the daytime version who set everything up.
That's the actual reason "how to block porn on Safari" gets searched again and again by the same people. The blocking works. The staying blocked doesn't.
Making it stick
Pledgely approaches Safari differently: it blocks adult content system-wide using Apple's Screen Time technology (Safari, other browsers, and apps), and backs the blocker with a pledge of your own money, $1 to $100 a day, set up on the web at pledgely.app. Visiting a blocked site is never logged and never charged; Pledgely collects zero browsing data. But switch the blocker off mid-cycle and your pledge is charged.
Blocking Safari takes five minutes with Apple's own settings. Making the block survive your own worst moment is what the stakes are for.
Put real stakes behind quitting
Pledgely blocks porn across your whole phone and charges your own pledge only if you turn the blocker off. Stay clean, pay nothing.