Blog

Why Is My Internet So Slow on My iPhone? What to Check

An iPhone lying on a kitchen counter at night, with a home Wi-Fi router glowing on a shelf behind it and a thin ribbon of light between them that loosens into a slow, tangled loop halfway across

Slow internet on iPhone usually comes down to the Wi-Fi, a setting like Low Data Mode or a VPN, or your provider. Quick checks, in order, to find which.

Marco Lee7 min read

Usually it’s the Wi-Fi, a setting on the iPhone, or your provider, and two quick tests tell you which. Check another device on the same Wi-Fi, then turn Wi-Fi off and try cellular. If everything on that Wi-Fi is slow, restart the router and check for an outage; if only the iPhone is slow, I’d look at Low Data Mode, any VPN or Private Relay, and how far you are from the router.

Is it the iPhone, the Wi-Fi, the provider or the site?

Two tests sort out most cases: try another phone or laptop on the same Wi-Fi, then turn Wi-Fi off on the iPhone (Settings > Wi-Fi) and load the same page over cellular.

  • Every device on the Wi-Fi is slow: the router or the provider. Apple’s advice: “If you can’t get online using your other devices, there might be a service outage. Contact your ISP” (Apple Support).
  • Other devices are fine, only the iPhone is slow: the iPhone, or where it sits. If other devices work on the network, “then the router and network are working” (Apple Support).
  • Slow on Wi-Fi, fine on cellular, or the other way round: the slow network is the problem, not the phone.
  • Only one site or app is slow: probably that site. If a problem “only affects a certain website or webpage,” Apple says to check Private Relay, then contact the site (Apple Support).

To put numbers on it, run the same speed test on both. The free FCC Mobile Speed Test app has a QuickCheck test that works “without submitting a challenge or sharing your contact information with the FCC” (App Store). Run it with any VPN off. Apple notes that with Private Relay on, “some speed test measurements may appear lower” (Apple Support).

Quick checks on the iPhone, in order

  1. Restart the iPhone. On iPhone X or later, hold the side button and either volume button until the slider appears, drag it, wait 30 seconds, then hold the side button until the Apple logo appears (Apple Support).
  2. Check Low Data Mode. Apple built it “to restrict background network use and save network usage,” and it “Reduces the quality of streaming content.” It isn’t a speed limit; Apple even suggests it “if you’re in an area with slow data speeds” (Apple Support). For Wi-Fi, go to Settings > Wi-Fi, tap the More Info button next to your network and look at Low Data Mode. For cellular on 5G, go to Settings > Cellular > Cellular Data Options > Data Mode; on LTE, the Low Data Mode switch is right under Cellular Data Options.
  3. Turn on Connectivity Assist if your Wi-Fi is patchy. It “uses cellular data to improve your connection when Wi-Fi is slow or unusable.” In iOS 27 it’s in Settings > Wi-Fi (scroll down); it replaces Wi-Fi Assist, which used to be in Cellular settings. It can use more cellular data (Apple Support). More in what Connectivity Assist is and when to turn it off.
  4. Turn off any VPN or Private Relay, then test again. Apple says software that “monitors or interacts with network connections can potentially block some connections,” including VPN, firewall and parental-control apps and content blockers. Turn its features off in the app, “then see if the issue continues” (Apple Support). For Private Relay, go to Settings > [your name] > iCloud > Private Relay, tap Private Relay, then Turn Off Until Tomorrow; it turns back on by itself within 24 hours (iPhone User Guide). If a VPN icon shows and you don’t know why, see why there’s a VPN icon on your iPhone.
  5. Look for big background transfers. With Background App Refresh on, apps can “check for updates and new content” while you’re not using them. Change it in Settings > General > Background App Refresh (Apple Support). iOS updates download in the background too: with Automatically Install on, your iPhone “downloads and installs the update overnight while charging and connected to Wi-Fi” (Apple Support). Other people’s downloads count too: the FCC notes that home service “often is shared simultaneously among multiple users and applications” (FCC, 2024).
  6. Move closer to the router. Apple lists “Connection is slow and signal strength is low” as a sign of interference, from things like “microwave ovens, fluorescent lights, wireless video cameras, and cordless phones” (Apple Support). If the router has two bands, Apple suggests trying another, “for example, join 5 GHz instead of 2.4 GHz” (Apple Support).
  7. Restart the router and modem. Unplug them and plug them back in, which “refreshes the network connection and can resolve minor connection issues” (Apple Support). To reach the router’s settings page, find its IP address on your iPhone.
  8. Update iOS, and reset network settings last. Go to Settings > General > Software Update. If nothing else works, go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. It “resets all Wi-Fi networks and passwords, cellular settings, and VPN and APN settings,” so Apple says to do it “only if other solutions fail” (Apple Support).

Why is my internet so slow on my iPhone but not other devices?

If other devices on the same Wi-Fi are fine, the router and the line are working, so the cause is on the phone or in the room. The usual suspects are steps 2, 4 and 6 above: Low Data Mode on that network, a VPN, Private Relay or a security app, or being farther away or on a different band than the devices that work. The FCC also notes that “some Wi-Fi connections may be limited to tens of Mbps” even when the plan delivers hundreds to the home (FCC, 2024).

Slow Wi-Fi alone doesn’t mean someone is on your network, but here’s how to check.

Why is my internet so slow all of a sudden, or at night?

If it was fine yesterday and is slow today on every device, I’d check the provider’s app or outage page and restart the router. If only the iPhone slowed down, look at what changed: a VPN you just turned on, an iOS update or backup downloading, or a new spot in the house.

Evenings are a known pattern. The FCC measures home broadband at “peak usage periods, which we define as 7 p.m. to 11 p.m. local time,” and says “speeds experienced by a consumer may vary during the day if the aggregate user demand during busy hours causes network congestion” (FCC, 2024). Busy cell sites slow down too (below).

When it’s your provider

On cellular, much of it is outside your phone. T-Mobile’s list includes “proximity to a cell site, the capacity of the cell site, weather, the surrounding terrain, use inside a building or moving vehicle,” plus your plan’s high-speed data allotment, video optimization and hotspot use (T-Mobile). Some plans put heavy users or cheaper plans lower in line, and those customers “may notice reduced speeds in comparison to customers with a higher priority during network congestion” (T-Mobile).

An outage is nothing you can fix on the phone. If speeds drop after heavy use, or only video or hotspot is slow, that may be your plan’s rules: is my internet being throttled? explains how to tell.

Can a VPN slow down my iPhone’s internet?

Yes, usually a little. With a VPN on, your traffic is encrypted and goes to the VPN server before it reaches the site, so a far-away location or a busy server can slow things down. If your provider slows one kind of traffic, a VPN can occasionally help, but it can’t make your connection faster than it already is.

The test is step 4: compare with the VPN off and on. The free VPN test shows the IP address and network websites see, so you can tell whether a VPN is in the path; it doesn’t measure speed. More in does a VPN slow down your internet?

When a site won’t load at all

That’s a different problem. Apple’s first steps: load a site such as apple.com over cellular or another Wi-Fi network, and check your VPN, since with one on “some apps or websites might block content from loading” (Apple Support). If one site still won’t open, it may be down, or blocked by your provider, a school or work network, parental controls, or your country. Rules on blocking and on VPNs differ by country and network, and some countries restrict or ban VPNs, so follow local law and your network’s rules. Is my ISP blocking a website? shows how to find out which.

What Mistero can and can’t do here

Mistero doesn’t measure your speed, can’t fix a weak Wi-Fi signal or a provider outage, and doesn’t list the devices on your Wi-Fi. Like any VPN, it adds a step, so if things are slow with it on, turn it off and compare. With Kill Switch on, which helps “stop network traffic if the VPN disconnects,” a dropped VPN connection can look like the internet stopped.

What it does: you can “Connect to available VPN locations in one tap” and “Mask your IP address while the VPN is active,” and its security checks can “Check Wi-Fi for visible connection or DNS anomalies.” The 4.0 release added “protocol selection, and recommended or streaming-optimized routes where available” (App Store listing, read Nov 6, 2026), so if a location feels slow, I’d try one closer to you, or a recommended route, and compare. More on Mistero VPN.

Sources

Pricing New subscribers can start a 3-day free trial. After the trial, the subscription renews automatically at $12.99 per week unless you cancel at least 24 hours before the trial ends, in Settings > [your name] > Subscriptions (Apple Support). There's also a one-time Lifetime purchase for $99.99. These are US App Store prices as of October 2026; the purchase screen shows the current price before you confirm.

Frequently asked questions

Why is my internet so slow on my iPhone but not other devices?

If other devices on the same Wi-Fi are fine, the router and your provider are working, so look at the iPhone: Low Data Mode on that network, a VPN, iCloud Private Relay or a security app, or simply being farther from the router or on a different band. Restart the iPhone and update iOS. Reset Network Settings is the last step, because it erases your saved Wi-Fi passwords.

Why is my internet so slow all of a sudden?

If every device slowed down at once, it's usually the provider or the router: an outage, a busy network in the evening, or a router that needs a restart. If only the iPhone slowed down, check whether a VPN or Private Relay was just turned on, or whether a big download such as an iOS update or iCloud backup is running. Heavy data use can also push you down the line on some mobile plans.

Does Low Data Mode make my iPhone internet slower?

Apple doesn't describe it as a speed limit. It restricts background network use: it turns off Background App Refresh, pauses automatic downloads, backups and iCloud Photos updates, and reduces the quality of streaming. So video can look worse and some things wait until you open the app, which can feel slower. If you don't need it, turn it off for that network.

Can a VPN make my iPhone internet slow?

Yes. A VPN sends your traffic through its server over your own connection, so it can't be faster than that connection, and a distant or busy server adds delay. Turn the VPN off and test again. If the difference is big, try a closer location. A VPN can't fix a weak Wi-Fi signal or a slow plan.
View All Blogs
VPN7 min read10 Nov, 2026VPN in Brazil: Is It a Crime, and Do You Need One?As of November 2026, no Brazilian law makes using a VPN a crime. What the 2024 STF fine over X covered, what the lei Felca says, and when a VPN helps.VPN7 min read10 Nov, 2026Do You Need a VPN in Japan? Legal, and When It HelpsMost people in Japan don't need a VPN at home. No law I found bans one, and it helps most on public Wi-Fi. What it changes, and what Japan-only apps say.VPN7 min read10 Nov, 2026Is a VPN Illegal in South Korea? And Do You Need One?I found no Korean law that bans using a VPN. What stays illegal with one, why some sites show warning.or.kr, and when a VPN actually helps in Korea.