Getting your boat or RV online — and keeping every sensor in range
Guardian can only warn you if it can reach you. That comes down to two separate problems: getting internet to your rig, and getting the signal around it. This page covers both, plus which SIM plans actually work.
The two problems, in order
Internet to the vehicle
A cellular router with its own SIM, or borrowed marina / campground Wi-Fi. This is the part most people think about.
Signal around the vehicle
Your sensors have to reach that router from wherever they live — including the bilge. This is the part that actually breaks, and it is usually free to fix.
Why sensors drop out — and the cheap fixes
Boats and RVs are close to worst-case for Wi-Fi. Steel and aluminum hulls, wet bilges, engine compartments, and the foil-backed insulation in most RVs all absorb 2.4 GHz signal. The distance is rarely the problem; what's between the sensor and the router usually is.
Your flood sensor is the one to watch
It sits in the worst spot on the vehicle and has the hardest job. To save battery it sleeps completely, then has to wake up and connect from scratch every time it reports. A mains-powered sensor can quietly retry a weak connection all day; a sleeping sensor gets one shot, and a marginal signal costs you battery life and, occasionally, an alert. If you fix coverage anywhere, fix it in the bilge.
Move the router
The single biggest win, and it costs nothing. Gateways end up shoved in a locker, a basement bay, or behind a metal panel — all of which kill signal. Get it up, out, and roughly central. Try this before you buy anything.
Add an external antenna
Most LTE gateways worth owning have screw-on antenna connectors. A better antenna, mounted somewhere with a view, beats a stubby one buried in a cabinet every time.
Add one repeater or access point
A single extra Wi-Fi node covers most boats and virtually every RV. Put it between the router and whatever is struggling — usually the bilge or a far cabin.
Fix the settings, not the hardware
Guardian sensors are 2.4 GHz only. A lot of "out of range" problems are really a sensor failing to join a combined 2.4/5 GHz network. Give 2.4 GHz its own network name, pin it to a fixed channel, and turn off band steering.
Work down that list in order. In our own testing, most "the sensor stopped reporting" reports turned out not to be range at all — they were a router with no antenna in a metal locker, a sensor on the wrong network, or a phone with Wi-Fi switched off. Check the simple things first.
Choosing a router
If you are buying one box for this, buy a small cellular router rather than relying on a phone hotspot. It stays powered, it stays aboard, and it does not leave with you.
GL.iNet Spitz series (GL-X750V2 / GL-X3000)
These are small, rugged LTE and 5G routers built for exactly this job, and they do something most gateways can't: they can use marina or campground Wi-Fi as their internet source instead of a SIM. That means one box works whether you have cellular, dock Wi-Fi, or both — and it can switch between them. They also have external antenna connectors, dual SIM on the newer models, and built-in GPS on some, which gives you location and geofence anti-theft for free.
Marina Wi-Fi is usually a weak signal from a long way off. A router that can grab it and rebroadcast a strong private network inside your rig solves the coverage problem and the internet problem at the same time.
Which carriers work
The router decides the carrier — not the plan
This trips up almost everyone. Cellular routers contain a specific modem, and that modem is only approved for certain networks. A cheap plan is worthless if your router cannot use it. Check the router first, then pick the plan.
AT&T and T-Mobile
The routers we recommend are certified for both. This is the path we support, and what we suggest for anyone who does not want to troubleshoot their internet connection.
On AT&T, look for their IoT / data plans rather than a consumer prepaid phone plan — consumer plans have been reported to fall back to slow speeds on this hardware.
Verizon
Verizon keeps a list of approved devices, and these routers are not on it — Verizon's own portal will label the router as an unrecognized device. Despite that, owners of the newer 5G models (GL-X3000, GL-XE3000) report running Visible and Verizon plans successfully for a year or more.
If you go this route: activate the SIM in a Verizon-approved device first (a hotspot or tablet), then move it into the router, and set the APN to vzwinternet. The older LTE-only GL-X750V2 will not work on Verizon at all.
We can't promise this keeps working — Verizon can change how it treats unapproved devices at any time, and there is no support path if it does. Choose it with that in mind.
Picking a data plan
Start by being honest about what the connection is for. If it exists only so Guardian can reach you, you need shockingly little data and should pay accordingly.
How much data does Guardian actually use?
Sensors that only report when something happens — a flood sensor, a door sensor — use almost nothing, single-digit megabytes a month. Add sensors that report continuously, like a battery-voltage monitor checking in every minute, and a typical setup lands somewhere around 100–300 MB a month. Either way it's megabytes, not gigabytes. Watch your first month's usage before committing to a bigger plan.
Just Guardian — sensors only
You want the boat watched and nothing else. No browsing, no streaming, no guests. This is the cheapest way to stay protected year-round.
Hologram
An IoT SIM that roams across networks. A typical Guardian setup lands around $4–6 a month all-in. Good coverage and a clean dashboard so you can see exactly what you are using.
1NCE Lifetime
One payment, ten years, 500 MB total — no monthly bill at all. That works out to about 4 MB a month, so it only fits a lean setup that mostly sits quiet and reports events. Top-ups are about $10 per 500 MB if you outgrow it.
Soracom
Another solid IoT SIM with worldwide coverage. Usually a bit more than Hologram at Guardian-sized volumes, but worth comparing if you cruise internationally.
Light use — cheap and unlimited, if you can live with slow
Sensors plus some email, weather, and a bit of browsing when you are aboard. You would rather never think about a data cap than have fast speeds.
Calyx Institute
A non-profit membership that includes genuinely unlimited data on T-Mobile. The cheapest honest "unlimited" available, and it works with the routers we recommend.
PCs for People
Another non-profit unlimited T-Mobile plan, with eligibility based on income or benefits. If you qualify, it is the least expensive unlimited option there is.
T-Mobile Business Internet
Unlimited and you can bring your own router. The catch for us: it wants a verified service address, which is awkward for something that moves.
Heavy use — this is your real internet
You work aboard, stream, run cameras, or have a family along. Guardian is a rounding error on this bill — buy for your life, not for the sensors.
AT&T Business Wireless Broadband
Unlimited, built for routers rather than phones, and officially supported on the gateways we recommend. The most predictable choice in this tier.
RoamLink (MobileMustHave)
Switches between AT&T, Verizon, and T-Mobile. On a boat, being able to fall back to whichever carrier reaches your anchorage is worth more than raw speed.
Starlink Roam
Different hardware entirely, but the honest answer once you are genuinely away from towers. See the off-season Standby tip below for keeping sensors alive cheaply in winter.
Carrier pricing and plan names change constantly, and availability varies by region — treat these as a starting point and confirm current terms before you buy. We are not affiliated with any of these providers.
Going Starlink? Get a month free
If you do choose Starlink (Standard or Mini) on a Roam or Residential plan, use a referral link from an existing customer before you check out and your first month is free.
Buy the hardware directly from Starlink.com — going through a third-party retailer like Best Buy or Home Depot voids the referral offer.
Off-season tip: Starlink Standby Mode
Own a Starlink on a Roam plan but leaving the boat for the winter? Switch the account to Standby Mode for about $10 a month. It pauses high-speed internet but keeps a roughly 500 Kbps trickle alive — far more than enough to keep your sensors reporting all season, for a fraction of the cost.
The short version
- Sensors won't stay connected: move the router before you buy anything. Then an antenna, then one repeater.
- Buying a router: get one that can also use marina Wi-Fi as its uplink. Check its carrier support before choosing a plan.
- Only protecting the rig: an IoT SIM for a few dollars a month is all you need.
- You also live aboard: buy the plan your life needs — Guardian's share of it is invisible.