International travellers can save money by renting a mobile hotspot that connects their phones, tablets and laptops to a local cellular network and avoids expensive data charges.

While wi-fi is becoming a common amenity in many parts of the globe, high-speed data connections are often expensive. You may face charges from the hotel or airport providing internet service, or from the local cellular company if you roam on its data network -- as most non-residents must.

So if you’re an international traveller that is also a heavy internet user, you may be able to save money by renting a mobile hotspot that connects directly to a local cellular network and avoids expensive charges for data usage.

This week, Hertz became the first car rental agency in Australia to begin renting mobile hotspots to its customers, having recently introduced the concept to selected locations in New Zealand, the United Kingdom, Spain and the Canary Islands.

But other companies have been renting mobile hotspots for the past three years. The devices are tiny and lightweight – they can sit in your pocket or backpack along with your tablet, smartphone and laptop – and after you initiate a connection, the hotspot automatically re-broadcasts the cellular signals from local mobile networks as wi-fi connections. Hotspots have an approximate four-hour battery life and come with local charging cables.

The cost of renting a mobile hotspot may be less than buying an international data package from your network provider. Rates vary by country and length of trip, but here’s an example: if you downloaded between 300 and 800 megabytes of data during a week in Western Europe, you would pay $120 on an AT&T international data package. Renting the Tep Wireless Pocket wi-fi mobile hotspot for the same number of days would cost about $64 for up to 500 megabytes of data (and an additional fee of $7 a day if you needed unlimited downloads).

In another perk, Tep and other wi-fi hotspots support multiple devices on the same connection, while cellular data plans only support a single device.

In general, pocket hotspots for all countries usually allow unlimited downloads, except for Thailand, whose local telecoms have stringent rules. But note that cellular networks in most countries have “fair use policies” that limit excessive downloading, such as consuming more than 500 megabytes in a week. Travellers who exceed limits may face reduced network speeds (down to 2G from 3G, for example) or lose access. That said, the typical smartphone user consumes around 25 megabytes a day and shouldn’t have problems.

Here’s a roundup of some of the most notable options.

Tep Wireless Pocket Wi-Fi
Available since 2011 through Tep, a British wireless technology start-up, travellers based in the US and Europe can rent a hotspot that automatically connects to local mobile networks in 38 European countries and the US. (The device comes in two versions, one for single-country use and one for pan-European use. There is no global, multi-country option) In October, Tep added coverage to 17 other countries, including Brazil, Russia, Singapore and China. Rental rates average $7 a day, but vary by country and the length of a trip. Tep also offers a device that for use in more than one European country on a single trip, with a sample 10-day, multi-country trip costing $85 plus shipping. Travellers can pick up (and return) a the rentable device at designated kiosks at Heathrow Airport and London’s Paddington Station for free, or pay shipping fees of between $22 and $30 to receive and return the device. There are caps on downloading that vary by country, but Tep’s is the most restrictive of the personal hotspots mentioned here, with a typical allowance of 150 megabytes per day.

International Mi-Fi Hotspot Rental
In 2010, Cellular Abroad began renting its first hotspot for use in Italy, and now its devices work in 130 countries, including Australia and China. Rates are for unlimited data consumption and vary by itinerary and length of trip, but a two-week trip to any of the largest European countries costs $15 a day. Usage across multiple countries on the same journey costs extra. There are no pick-up locations, so to receive and return the device, you must pay a shipping charge, which is usually $13 in total.

XCom Global MiFi
With the broadest coverage of these devices, XCom Global MiFi debuted in 2010 allowing travellers to take advantage of local networks — usually 3G (though it offers 4G in Japan) — in 174 countries, including 40 European countries such as France and Bulgaria. The flat rate is $15 a day for the first two countries you visit, with a $30 charge for each additional country. XCom offers unlimited data. So far, the only pick-up spot is a counter at Los Angeles International Airport and an Amnet travel agency near Grand Central Station in New York City, so most customers will need to pay for shipping to receive and return the device for a fee that’s usually $30 round-trip for North American travellers.

Hertz Mobile Wi-Fi Hire
The rental car chain rents portable wi-fi hotspots in major airport and city centre locations in Australia and the United Kingdom, plus at Auckland airport in New Zealand, Madrid Airport in Spain and Grand Canaria Airport in the Canary Islands. Customers pick-up and drop off the device at a Hertz location (no shipping option), and you don’t need to hire a car to get the service. Costs and usage caps vary by country, with a daily cap of 150 megabytes of downloads being typical. Visit the Hertz website and select your destination country and then click on Products & Services on the homepage menu to see details.

Sean O’Neill is the travel tech columnist for BBC Travel