Wi-Fi Roaming UniFi & iPhone & Android

People expect to walk around a home or office mid-call without the Wi-Fi dropping. With several UniFi access points and a building full of iPhones, getting roaming right takes more than ticking a box — here is how we approach it.

Updated September 2026 for UniFi Network 10 and Apple’s current Wi-Fi roaming guidance, including Wi-Fi 7 and 6 GHz.

Why roaming goes wrong

Most installations we are called in to fix have one or more of these four causes.

There is no single setting that fixes every site. Understanding radio propagation, antenna patterns and raw signal data is the starting point, and years of on-site experience are the biggest advantage. Android phones vary widely depending on the model and Wi-Fi chipset. Apple devices behave consistently, but they are less forgiving of a poorly designed network, so this guide focuses on iPhone, iPad and Mac.

How an iPhone decides to roam

In Wi-Fi, the client — not the access point — decides when to roam. Apple devices watch the signal strength (RSSI) of their current access point and only start looking for a better one once it falls past a roam trigger threshold. A candidate then has to be meaningfully stronger before the device moves.

A worked example: during a Wi-Fi call, an iPhone’s signal drops to –75 dBm. It will now only move to an access point it hears at –67 dBm or better. If the call ends and the phone goes idle, the bar rises to –63 dBm. A Mac in the same spot also needs –63 dBm.

This has a practical design consequence. If you plan cells with a –67 dBm overlap, an iPhone will stay on its current access point longer than you might expect, because it does not even start looking until –70 dBm.

What makes one access point more attractive than another

Signal strength is not the only factor. Apple devices also weigh how busy each channel is and how many clients are already connected, then score the candidates. Where scores are close, they prefer newer standards — Wi-Fi 7 over Wi-Fi 6, Wi-Fi 6 over Wi-Fi 5, and so on — and wider channels, from 160 MHz down to 20 MHz. On 6 GHz, devices also discover networks through information advertised in 2.4 GHz and 5 GHz beacons.

Wider is not automatically better in a multi-access-point building, though. Narrower channels leave more room for neighbouring access points to avoid each other, which usually matters more for smooth roaming than headline speed.

The roaming standards, and where they live in UniFi

Finding the right access point is only half the job. The phone then has to re-authenticate quickly enough that a call does not notice. These are the technologies that make both halves faster.

• 802.11k (radio measurement): the access point gives the phone a neighbour list, so it scans a handful of likely channels instead of every channel in every band. Apple devices use the first six entries. Without it, finding a roam target can take several extra seconds. Supported by Apple and UniFi.
• 802.11r (Fast BSS Transition): shortens re-authentication when moving between access points on the same network. In UniFi this is the Fast Roaming option. Apple’s “Adaptive 802.11r”, which lets older devices share an SSID with fast-transition clients, is a Cisco-specific feature rather than a UniFi one.
• 802.11v (wireless network management): lets the network suggest the best access point to move to. In UniFi this is BSS Transition; in UniFi Network 10.4 the related Roaming Assistant was renamed Handoff Suggestions and extended to 6 GHz.
• PMKID caching: speeds up reconnection to an access point the device has already authenticated with. All Apple devices support it, including those without 802.11r.
• 802.11u (Hotspot 2.0 / Passpoint): lets devices move automatically between trusted networks without new sign-in details, much like mobile roaming. Supported by Apple and UniFi.

Security choice affects roaming speed too. With 802.1X (WPA-Enterprise), a device without fast roaming must complete the full EAP exchange before it can pass data on the new access point, which can take several seconds depending on your authentication servers. UniFi Wi-Fi 6 access points support 802.11a/b/g/n/ac/ax with WPA-PSK and WPA-Enterprise (WPA, WPA2 and WPA3). UniFi Wi-Fi 7 models add 802.11be and PPSK.

Know your access point’s radiation pattern

Different UniFi models radiate in very different shapes, and that changes how and where they should be mounted. Ubiquiti publishes antenna radiation patterns for every UniFi access point. Compare the U6 Lite and U6 Mesh below.

Configuring UniFi for iPhone roaming

Every site is different, so treat these as a starting point and change one thing at a time.

1. Update everything

   Run current firmware on the UniFi Network application and every access point. Roaming fixes arrive regularly.

2. Start from Auto

   Leave Wi-Fi settings on automatic and test by walking the building with the Ubiquiti WiFiman app on an iPhone. Only tune what testing shows is wrong.

3. Check the iPhones

   Turn off Wi-Fi Assist while testing, so the phone does not quietly fall back to mobile data and hide the problem.

4. Watch the roams

   Use Clients and Events, plus the roaming journey view and WiFi Doctor added in UniFi Network 10.1, to see exactly where phones stick or drop.

Design and radio

• Cable, don’t mesh. Wired backhaul is faster and more consistent. Mesh only where cabling is genuinely impossible.
• Keep SSIDs to four or fewer. Every extra network adds beacon traffic that eats airtime.
• Don’t set every radio to High. Auto or Medium is usually better. Wi-Fi is two-way, and a phone transmits at far lower power than an access point, so a loud AP can be heard by a phone that cannot reply. Lower power also encourages earlier handoffs in dense deployments.
• Avoid DFS 5 GHz channels for voice. Phones must listen before using them, which slows scanning, and radar detection can force an access point off its channel mid-call.
• Minimise channel overlap. Give neighbouring access points non-overlapping channels and check the result in UniFi’s wireless overview.
• Hunt down interference. Check neighbouring Wi-Fi, TVs (which tend to shield), motors, microwaves, and access points mounted on or near high-power equipment or cabling. Thick or reinforced walls block signal badly.

SSID settings

• Fast Roaming (802.11r): on.
• BSS Transition (802.11v): on.
• Band Steering: usually works well; toggle it while testing if phones sit on 2.4 GHz.
• UAPSD: a client power-saving feature that generally works well and helps battery life. If a particular device misbehaves, test with it off.
• Multicast and Broadcast Control: worth enabling on networks with more than 100 clients, together with Multicast DNS. Add AirPlay, Chromecast and printers to the exclusion list so they keep working.
• DTIM period: leave at the default. DTIM controls how often sleeping clients wake for broadcast and multicast traffic — it affects battery and IoT responsiveness rather than roaming. If IoT devices struggle, use values of 1 to 3 or give them their own SSID; newer UniFi releases add a DTIM Interval Lock for this.
• Minimum Data Rate Control: leave on Auto for maximum compatibility, or 5.5 Mbps on 2.4 GHz and 6 Mbps on 5 GHz for older IoT devices. On a voice-focused SSID with no legacy clients, raising 5 GHz to 12 Mbps shrinks the usable edge of each cell and nudges phones to move sooner.

Minimum RSSI: a last resort

Minimum RSSI makes an access point disconnect clients whose signal falls below a set level. Leave it off while you test. It only kicks a device off — it does not tell it where to go — so a badly chosen value causes drops rather than smooth roams.

Rarely needed

• A dedicated 5 GHz SSID for iPhones can help in difficult environments, but it adds an SSID and should only follow proper design work.
• Changing the beacon interval is something we no longer recommend. A shorter interval adds airtime overhead on every channel and does not reliably make iPhones roam sooner.

Further reading

• Apple: Wi-Fi roaming support in Apple devices
• Apple: iPhone roaming specifications
• UniFi: understanding and implementing minimum RSSI
• Video: roaming options explained in detail

As a Ubiquiti partner, we design, survey and tune UniFi networks for homes and businesses, including network installation and Wi-Fi for VoIP phone systems.