Why Cell Coverage Gives Up Once You Leave the Harbour
Ever notice your phone still shows bars crossing Tauranga Harbour, then drops out not far past the entrance? Mobile towers are built and aimed to cover land, not water, and the curve of the earth does the rest. The higher your boat's antenna and the taller the tower, the further you'll get, but there's always a point where the signal simply runs out.
Weather doesn't help either. Rain, sea spray and low cloud all knock a small margin off an already weak signal. Combine a few kilometres of distance with a bit of chop and most phones are already done well before you're genuinely offshore.
A satellite phone skips ground infrastructure entirely. As long as you've got a reasonably clear view of the sky, it talks straight to a satellite instead of a tower, which is exactly why it keeps working long after your phone has given up.
Where a Satellite Phone Actually Fits Alongside VHF and Your EPIRB
Here's the part a lot of guides skip. A satellite phone is not your primary safety device at sea, and it's not a replacement for what you should already have on board.
VHF Radio Stays Your First Call
VHF channel 16 and your local Coastguard network are still where a genuine emergency call starts if you're within range. In the Bay of Plenty, Tauranga Coastguard monitors channel 01, with repeaters covering the Kaimai Ranges on channel 62 and Mayor Island on channel 66. That network reaches other vessels and Coastguard directly, which a satellite phone call to a shore-based contact can't replicate in the same way.
An EPIRB Is Still Your Last Resort
If things go seriously wrong, a registered EPIRB sending a 406MHz distress signal straight to Rescue Coordination Centre New Zealand is still the tool built specifically for that moment. A satellite phone call can support a rescue by giving responders detail and context, but it shouldn't be the only distress option on board. If you don't already carry one, our Personal Locator Beacons and EPIRBs page covers what NZ vessels need.
So What's a Satellite Phone Actually For?
A satellite phone is for the two-way voice contact that VHF and an EPIRB can't give you. Calling the office, checking in with family, getting a detailed marine weather update from a forecaster rather than a broadcast, or simply staying reachable on a multi-day trip well beyond VHF range. That's the gap it fills, and it's a genuine one for any crew regularly working offshore.
For the fuller picture on how VHF, AIS, EPIRBs and satellite phones fit together on a NZ vessel, our complete guide to marine communication covers the whole stack in more depth.
Choosing the Right Handset for Real Conditions
Two satellite networks cover New Zealand waters, Iridium and Inmarsat, and the choice comes down to what you actually need, not brand loyalty.
Iridium: Global, Including the Poles
Iridium runs a low Earth orbit constellation of 66 satellites that circle pole to pole, giving genuinely global coverage including the open ocean and higher latitudes. That constantly moving constellation is a real advantage if you're crossing open water rather than staying close to a single stretch of coast.
Inmarsat: Reliable Near-Global Coverage at a Lower Price
Inmarsat's satellites sit fixed in geostationary orbit above the equator, giving strong coverage everywhere except right at the poles, which for most NZ coastal and offshore work is no real limitation. It's typically the more affordable entry point into satellite voice.
Whichever network you land on, the deciding factors on the water are the same: how long the battery lasts across a full day or overnight, how well the handset copes with salt spray and knocks around the deck, and whether you need data and email as well as voice.
That's the Iridium GO!, worth a look if what you actually want is weather routing, email and messaging through apps on a phone or tablet you already own, rather than a dedicated handset.
What MSL Actually Recommends, By Device
All currently in stock and priced in NZD. Here's what we'd point a crew toward depending on how you actually use the boat.
Best Value
Inmarsat IsatPhone 2 — $1,9768 hours talk time, up to 160 hours standby, IP65 rated. The most affordable genuine entry into satellite voice.
View IsatPhone 2 →Best All-Rounder
Iridium 9555 — $2,595Compact and straightforward, the phone most commonly seen on boats needing solid, no-fuss satellite voice.
View Iridium 9555 →Best for Deck Use
Iridium Extreme 9575 — $2,965IP65 rated, MIL-STD-810F tested, with a dedicated one-touch GPS SOS button. Built for handling with wet or gloved hands.
View Iridium Extreme →Best for Data and Weather
Iridium GO! — $2,101Turns up to five paired devices into satellite-connected phones and tablets for weather routing, email and messaging.
View Iridium GO! →Don't Forget the EPIRB
A satellite phone is a genuine upgrade to your comms, not a substitute for your primary distress beacon. If you're reviewing your safety gear at the same time, the GME MT605G ($530) covers the core manual-activation requirement, while the GME MT606FG ($1,399) adds float-free auto-deployment and AIS alerting to nearby vessels if your boat goes down.
Browse the full range in our marine communications collection, or if you only need a handset for an occasional trip, check Satellite Phone Hire rather than buying outright.
Getting Set Up Before You Head Offshore
A satellite phone in a drawer with a flat battery isn't a safety system, it's a false sense of security. Getting it genuinely ready takes a few simple steps.
You Need Airtime, Not a Radio Licence
Satellite phones run on networks already licensed overseas, so there's no individual NZ radio operator licence to hold. What you do need is an active airtime plan through a reseller such as Pivotel, activated before you leave, not something to sort out once you're offshore.
- Confirm your plan is active. A satellite phone with no airtime plan is just an expensive paperweight.
- Test it before you leave the marina. Confirm a clear call and check the antenna has an unobstructed view of the sky from wherever it'll sit on board.
- Check your EPIRB registration is current. Registering with RCCNZ is free and separate from your satellite phone's airtime plan.
- Mount it somewhere it'll survive the trip. Salt spray and a hard deck are not kind to electronics left loose in a pocket.
Not sure which handset or plan actually fits how your boat operates? Get in touch with our team and we'll match the gear to the trip, not the other way around.
