WiFi calling abroad - off or on to save cost

[RobinF1957]

I am to travel to France shortly. EE advise to turn WiFi call OFF to save costs. This seems counterintuitive to me. 

[bristolian]

WiFi-calling is a coverage-enhancement facility designed for UK-use, and calls are charged exactly the same as if they were made over the mobile network.

It isn't supported abroad, but if it does work, standard roaming charges will apply.

WiFi-calling has never been intended as a means to avoid call charges, and it shouldn't be treated as such!

[Rich4rd]

Completely agree, but in what circumstance would Wi-Fi calling be more expensive?  Why would you turn it off?