The estimate was made by Syniverse, which claims, not surprisingly, to have "uncovered the value of a significant segment of mobile end users who are willing to go to great lengths for connectivity when they leave home beyond those options enabled by their home mobile service providers."
What is perhaps surprising is that these mobile service providers - well known for their high roaming charges - are Syniverse customers: it supplies technology and services to support roaming between different operators.
"Transient roamers represent a significant portion of the mobile ecosystem, and their requirements for consistent, high-quality connectivity are growing exponentially," Syniverse president and CEO Jeff Gordon said.
He suggested: "This segment provides an opportunity for the myriad of mobile service providers to enable seamless connectivity across the ecosystem, managing end-user experiences in real time and solidifying each provider's place in the value chain."
Syniverse says it calculated the 'transient roamer' potential based on "expert insights into average roaming volumes, end-user roaming habits and third-party travel and roaming reports."
It estimated hotel Wi-Fi to be the biggest component, US$8.7b, Other Wi-Fi hotspots accounted for US$3.9b and US$4.8b was spent on charges through locally purchased SIMs. In flight Wi-Fi contributed a modest US$225m to the total.
One figure quoted by Syniverse appears to make no sense at all. It calculated that 'silent roamers', those who greatly diminish or cease using their mobile service altogether represented an annual missed revenue opportunity for mobile service providers of US$1.2b. In other words, travellers are spending far more on alternatives than they would if they used operators' international roaming services!
Syniverse does not suggest that operators should reduce their roaming charges. Instead it says that "With instantaneous visibility into the trillions of transactions that traverse mobile networks each year, Syniverse is able to deliver real-time experience management to mobile service providers, enabling them to interact with end users before they become silent or transient and to deliver relevant, compelling service offers across mobile and Wi-Fi."
To bridge mobile networks with the world of Wi-Fi for these transient roamers, Syniverse says it has developed a number of Wi-Fi interoperability solutions that cover the range of needs from reach to facilitation of clearing to enabling voice and messaging traffic to traverse a Wi-Fi network.