inReach Phone Number

I have seen this, too. My guess is, the messages went via different Garmin servers and so each message may get a different phone nummber assigned. Unfortunately the Garmin IR devices have no own phone number (like Zoleo and others are handling this). I hope I wrote no nonsense.

Btw: screentime contact limits: open a support ticket.

No way around protection on your kids' phones I'd say. No static number = nothing you can add to the list...(UPD I've asked at the store I've got it from and they basically said what Volker wrote above).

No inReach device has a permanently assigned phone number. The "from" number on an SMS message sent from the inReach is a temporary assignment. Yes, the recipient can reply to that number using the normal SMS app on their phone. However, the ability to do even that much is temporary. Nobody know for sure how long the ability lasts, but it is on the order of a few weeks.

The way this works:

iR sends a message to an SMS number.

Messages transits the Iridium network and the Internet to the Garmin servers.

Garmin servers forward it to an SMS gateway. Not sure the gateway is chosen, but it depends in some way on the recipient's cell provider.

The gateway forwards the message to the recipient's cell provider. The gateway uses a temporarily assigned "from" number for this.

The gateway reports the from number back to the Garmin servers. The servers record the to number, the from number, and the identity of the iR device. This record is used to route any reply. The servers remember this pair of numbers for a limited time.

The recipient's cell network forwards the message to the recipient using the temporarily assigned from number.

Recipient replies to that from number.

The reply SMS message follows the same path in reverse order. The gateway associates the temporary from number with Garmin, and forwards the reply to the servers. (In the reply, the "from" number is the recipient's cell number. The "to" number is the temporarily assigned from number for the original SMS message.) The servers match the numbers to get the iR device ID. The servers route the reply to the correct device via the Iridium network.

the term is called 'large account' and this has to be booked at the provider running the particular network. This will then dynamically supply the 'from' numbers and thus a way back. Local network operator will be chosen if possible.

This was av since beginning of GSM, but probably also on earlier mobile systems. However there were many operators not willing to switch on such feature.

Earlier, one had to book such service with each single network operator, today some specialized agencies will organize that for worldwide operation.