Q: how do I turn off my iPhone so it only works on wi-fi in another country?

Enable Airplane Mode first followed by turning on Wi-Fi. All other iPhone radios will be off except for Wi-Fi.

Would it also work by doing the following?

Settings>General>Network>Roaming>turn both voice roaming and data roaming to OFF

What would be the difference between enabling airplane mode+turn on wifi and turning off voice+data roaming?

Or simply remove your SIM card. All radios on iPhone will work, but it won't have phone connection.

JP

Our network does not utilize a SIM card

Data Roaming off prevents data or internet access via a carrier's cellular network when roaming internationally. This does not prevent being able to place to receive any calls and the same for SMS.

Your question is how do you turn off your iPhone so it only works on wi-fi while in another country, and the answer to that question is enable Airplane mode followed by turning on wi-fi. All other iPhone radios will be off except for wi-fi.

If the question is how do I prevent data or internet access only via a carrier's cellular network when roaming internationally and keep the ability to place/receive calls and the same for SMS when doing so (MMS and iMessage will not work without having cellular data or internet access), the answer to that is turn Cellular Data off.

Removing the SIM card is an option but you won't be able to place or receive any calls and the same for SMS with the SIM card removed plus having to store the SIM card in a safe place so it can be recovered when needed.

What happens when you turn voice roaming OFF?

Will it prevent you from making and receiving calls and SMS?

I'm not familiar with voice roaming. There is no voice roaming setting with a GSM iPhone.

What are you wanting to prevent?

If you want to prevent the ability to place or receive any calls and the same for SMS/MMS when roaming internationally, do as I provided. That ensures all iPhone radios are off except for wi-fi.

Just put your iPhone in airplane mode or remove your SIM card, either of these will work the best compared to all other methods.