An Ericsson survey of WiFi callers found more than 61 per cent of respondents in the US made longer and more frequent calls, while 53 per cent dropped some WhatsApp usage in favour of WiFi calls.

Other findings from Ericsson ConsumerLab include that 55 per cent of respondents have increased SMS usage when WiFi coverage fills a gap in cellular coverage.

The survey notes the importance of network coverage to determining customer loyalty among users in the US (the same is true of other countries), and that WiFi callers are more likely to be an advocate of an operator.

The main thrust of the survey is international travellers, many of whom cut down usage when abroad even if they have a corporate mobile plan (employers frequently set upper limits on usage or expense).

Around half of respondents said they make over six out of ten voice calls abroad using apps provided by so-called OTT providers. Others switch off their phones.

A third of respondents were aware of Wi-Fi calling, 20 per cent had heard of the service but were unsure how it works. Over half had not heard of it. However, most found the concept appealing once explained.

Given an option of VoWiFi, travellers anticipated that voice’s share of their daily usage would increase from 30 per cent to 40 per cent. They might also drop some pre-travel planning, such as purchasing a local SIM or setting a specific tariff from their operator.

The online survey was conducted among 5,000 smartphone users who are also international travellers. They came from Brazil, Egypt, Spain and the UK, as well as the US.