It's the dream holiday – France, Spain and Italy spread out over three blissful weeks. Fascinating places and indulgent dining help take you far, far away from the worries of daily life. The cost of your next mobile phone bill isn't exactly front of mind. But that all changes soon after you get home, in what proves the ultimate post-trip dampener.

THE RISKS OF ROAMING

Very high costs for global roaming used to simply be an accepted fact, but with the advent of the more cost-effective international SIM card back in the early 1990s, the major mobile phone networks have increasingly come under scrutiny for charging what many people view as excessively high rates.

Queensland-based TravelSIM is one of the companies leading the way in the international SIM card revolution. Chief executive Jamien Zimmermann said that despite many stories in the media about travellers returning to huge bills after overseas trips, Australians weren't as aware of the costs of global roaming as they should be.

"Part of the issue is that travellers tend to think that they will be able to limit their phone use. The problem with that thinking is that unless the traveller has a way of containing global roaming costs in place from the start, a single call back home, made in a happy moment or because there is a crisis, can add up to hundreds of dollars," he said.

Another key player in this area is Melbourne-based Roaming Solutions, which sells the product RoamingSIM. Director Jonathan Hume said data usage (such as internet, email and apps) was often the culprit, as it had huge international roaming costs attached to it.

CAUSE FOR COMPLAINT

And there are more than a few unhappy mobile phone customers out there, according to statistics from the Telecommunications Industry Ombudsman (TIO). Figures showing the number of complaints where consumers had a disputed bill with high roaming charges found that during the five quarters from January 2011 to March 2012 there were 5083 complaints.

Hume said the cost of international roaming charged by the major Australian telcos was "astronomical and in our opinion, totally unacceptable.

"The cost for calls and data usage is generally 80% to 90% higher than it should be, which generates huge roaming bills for ordinary travellers. As an example, Optus charges $20 per MB for data in many popular European countries, where RoamingSIM is 61 cents per MB, and even less with the use of data bundles now available for the UK or Europe," he said.

Local consumer groups have long been calling for new Australian laws to force mobile phone companies to limit consumers' exposure to global roaming fees. Such legislation is already being enacted in other parts of the world, such as Europe, where mobile networks are slashing roaming rates and creating continent-wide "Euroaming" deals covering most of the region.

SIM-PLY THE BEST

Hume said international SIM cards generally charged up to 90% less for roaming than the major telco companies, with this applying to voice calls, as well as data usage.

"The biggest benefit is that the account is prepaid, meaning you can never spend more than the credit that is on your account. It gives the traveller full control of their roaming costs, and enables them to use their phone or device without worrying about coming home to a scary bill," he said. "Data is gaining rapidly in popularity (over 50% of our business is now data) from use in smartphones and iPads, so a cheap roaming option is becoming more important than ever." Besides TravelSIM and RoamingSIM, other key players with local operations include Gotalk and Go-SIM.

TOOLS OF THE TRADE

Because most consultants are veteran travellers, they can sometimes overlook the fact that their clients might need to be guided on the best way to communicate from overseas, according to Zimmermann.

"The first rule for the travel agent should be to add value through educating your clients about global roaming," he said. "People need to know that even if their phones work abroad, they shouldn't expect the same continuity of service and pricing that they have back home. The travel agent should also be able to offer strategies and solutions – preferably an international pre-paid SIM – to equip their clients with the right tools." Local SIM cards were often hard to obtain, he added.

Hume suggested that travel agents always ask their client if they were intending to take a mobile phone, tablet or laptop. "If they are, recommend an international SIM card to avoid bill shocks on their return. Tell them it's easy to set up and all they need is an unlocked mobile device. Tell them the SIMs can be used for voice, data and text and are available for use in standard or micro size."

And the great bonus for consultants to remember is that many international SIM card providers offer generous commissions.