Ubiquiti announced a new travel router. Much of the internet is excited. So am I.

Then I tried to remember the last time I actually needed a travel router. You see, Android has supported a feature I’ll call Wi-Fi sharing for years.1 Your phone connects to an existing Wi-Fi network and re-shares it as a hotspot.

This might sound like a regular hotspot feature that most phones (including the iPhone) come with. But it’s not. iPhones can share mobile data. They can’t re-share a Wi-Fi connection as a hotspot.

Wi-Fi sharing

Your phone connects to Wi-Fi, and then re-shares that same Wi-Fi as a hotspot.

 

This is different from typical hotspot functionality where the phone shares its mobile data connection (vs Wi-Fi).

Neat trick, but why bother? Can’t you just connect each device to Wi-Fi?

Avoid signing every device into a captive Wi-Fi portal #

Captive portals are annoying when you’re carrying multiple devices. I typically travel with 3-4 devices that want internet. Signing each one in, every time, gets old fast.

Some devices are worse: Chromecast and Fire TV sticks are particularly painful to get past captive portals. If everything connects to your hotspot, you only deal with the portal once.2

Work around “one device at a time” Wi-Fi plans #

On a plane, I sometimes want both my laptop and phone online. Some paid Wi-Fi plans only allow one device at a time. Unless you’re ok paying twice, Wi-Fi sharing is simpler.3

Hotels and conference centers do the same: sign-in plus device limits. Wi-Fi sharing works around it.

Fix “devices can’t see each other” networking #

This one is less obvious, but common in hotels and conference Wi-Fi: your devices have internet, but they can’t see each other locally. Chromecast (or printers) won’t show up as a cast target because it doesn’t appear on the network.

That’s usually client/AP isolation.4 Put your devices on your phone’s hotspot, and local discovery usually works again.

Secure networking with a Tailscale setup #

This is slightly advanced. With a Tailscale setup and an explicit exit node, you basically have a private VPN.5 On phones where hotspot traffic routes through that VPN, you only have to set it up on your Android phone, and every device that connects to your phone gets the same “safe” path out.

If I have to log in to bank accounts when roaming or connecting to “free” Wi-Fi, this helps me feel safer knowing the local network can’t see or tamper with the contents of my traffic.6

How to enable Wi-Fi sharing #

  1. Connect your Android phone to the Wi-Fi network you want to share. If it’s behind a captive portal, sign in as needed.
  2. Go to Settings → Hotspot & tethering → Wi-Fi hotspot (wording varies) and turn it on.

Typically, if your phone does not support Wi-Fi sharing, it will disable Wi-Fi. Some OEMs show a separate toggle to enable Wi-Fi sharing. On Pixel phones, it’s automatic.

Almost every Android phone #

I should pause my gloating over iPhones for a second: a few Android devices may not support this feature.

The Android OS has Wi-Fi sharing baked in, but it still requires hardware + driver support. Notable exceptions include the Pixel 7a, the Pixel 8a, and yes the (first generation) Pixel Fold.

Technical Details #

Wi-Fi sharing requires Wi-Fi hardware (chipset + drivers) that can run as both a client and an access point at the same time (STA + AP).7 Chipsets can implement this in a few ways (DBS, SBS, MCC, SCC).8

Android doesn’t mandate one mode; it depends on the Wi-Fi chipset. DBS/SBS use multiple radios, so the phone can keep the upstream connection and hotspot truly simultaneous (for example, 5 GHz upstream and a 2.4 GHz hotspot). MCC/SCC share a radio, so the hotspot either stays on the same channel (SCC) or the radio hops channels (MCC).

If a phone can’t do STA + AP concurrency well (or at all), OEMs disable Wi-Fi sharing (which is why some phones and many older devices don’t support it).

Travel routers still have their place: Ethernet ports, better radios, and an always-on box you can run a VPN on. But if you’re on Android and your phone supports Wi-Fi sharing, you already have the core trick.

  1. Android doesn’t call it this in Settings, but it’s the best term I have for “connect to Wi-Fi, then share that Wi-Fi as a hotspot”. In strict networking terms, this isn’t L2 bridging; it’s typically tethering (routing/NAT) with a Wi-Fi upstream. ↩︎

  2. This works because the captive portal only sees your phone; everything else is NATed behind it. ↩︎

  3. Thank you Delta for being one of the few US domestic airlines that don’t place this restriction. Looking at you United. ↩︎

  4. Hotel and conference Wi-Fi often blocks device-to-device traffic on purpose (“client isolation”) so guests can’t discover, scan, or connect to each other’s devices. Your phone’s hotspot creates a separate little LAN, so your devices can talk to each other again. ↩︎

  5. I have a post in the making about this: “With Tailscale you don’t need to pay for a VPN”. ↩︎

  6. HTTPS encrypts the bank session, but open Wi-Fi is still untrusted: a malicious access point can tamper with DNS and try to steer you into phishing. A VPN (or Tailscale exit node) reduces the surface area by encrypting your traffic to a trusted endpoint. ↩︎

  7. Modern devices support AP (Access Point) + STA (Station) Mode, letting them act as both a client to one network and a hotspot for others, allowing Wi-Fi extension or tethering. ↩︎

  8. Definitions from Android’s Wi-Fi vendor HAL (WifiNative.java): DBS (Dual Band Simultaneous), SBS (Single Band Simultaneous), MCC (Multi Channel Concurrency), SCC (Single Channel Concurrency). ↩︎