Here's how to prevent having your mobile number recycled while you're overseas

If you’re heading overseas for a few weeks or even a few months, and you’ve decided to purchase a local SIM card when you land, rather than use your carrier’s expensive global roaming service — good decision, by the way — you may be in for a shock when you return to Australia and try to use your Australian mobile number.

If your mobile service is inactive for a period of time (usually six months, sometimes less), your carrier may decide to disconnect your mobile number, and if this happens, you could lose it for good.

After a mobile number — or indeed any telephone number in Australia — is disconnected, it’s “quarantined” for six months (or 12 months if it was disconnected due to complaints of nuisance calls).

During this quarantine period, the number can be reissued to you and only you; you just need to contact the last carrier the number was connected to, and request they reconnect the number.

However, after this quarantine period, the number is returned to the carrier that first issued it. That number can now be recycled and issued to a new customer. You can ask to have that number reissued to you, but the carrier controlling it is not required to let you have it back.

So, what can you do to make sure your mobile number isn’t recycled?

Well, you need to make sure you keep the account active. However, some carriers make this easier than others.

All three of the major mobile carriers — Telstra, Optus and Vodafone — have prepaid mobile plans with long expiry periods, which means you can keep your mobile account active for several months with a single recharge.

Telstra

Telstra’s long expiry offering is called Long Life. A $20 recharge lasts for 60 days, and a $30 recharge lasts for six months. However, from that balance you’ll be paying $2 to download 1MB, 29c to send a text message, and 78c per minute plus a 39c connection fee for standard national phone calls.

Optus

Optus’s long expiry offering is called My Prepaid Long Expiry. A $10 recharge will last 186 days (about six months), however, that’s only if you recharge before April this year. If you recharge after April, you’ll have to pay $30 to keep your number active for that same period of time. Additionally, from that balance you’ll be paying 5c to download 1MB, 20c to send a text message, and 20c per minute for standard national phone calls.

Vodafone

Vodafone’s long expiry offering is called Pay As You Go Plus. A $10 recharge will last 365 days, and from that balance, you’ll be paying 2c to download 1MB, 2c to send a text message, and 20c per minute for standard national phone calls.

As you can see, Vodafone’s offering is clearly the best if you just want to load the minimum amount possible onto your mobile account so your number stays connected. However, Vodafone’s network is not nearly as good as the other two providers’, so you’ll need to take that into consideration.

If your mobile is on a plan with a lock-in contract, you’ll need to do the maths and determine whether it’s worth breaking your contract and paying the exit fee and remaining handset repayments, or just sticking the contract out, even if you’re not actually using your Australian SIM card.

Mobile carriers change their offerings all the time, so make sure you check the expiry periods and costs on their websites.