SIM only is a type of mobile plan where you pay for calls, texts and data. The SIM usually comes included with the plan and you don't get a phone with the SIM, which is why it's known as "SIM only" or a BYO phone plan.
A SIM only plan can traditionally be categorised as one of 2 types: prepaid or postpaid.
The main difference between them is when you pay for your mobile plan. With prepaid, you'll pay upfront at the start of the month before you start using your plan, whereas on postpaid it's normally at the end of the month.
In some instances, providers such as Telstra will make you pay at the start of the month even on a postpaid plan so keep an eye out for this to avoid any surprises.
"I've been using SIM only plans for years now. It's got to be one of the easiest things to switch so I change providers every year. There's always a different deal worth snapping up."
In Australia, it's still common to get a SIM card with your mobile plan. You will usually need to buy a SIM card from the store or order it online. The SIM will then need to be inserted into your phone so you can activate your plan.
Some providers also offer the option to sign up with an eSIM, which is a newer technology rolling out in Australia.
An eSIM allows you to set up your mobile plan digitally without the need of a physical SIM card, meaning you don't have to wait for your SIM to arrive by post. This can be especially useful when you're travelling overseas.
Some of the cheapest SIM only plans on Finder come from providers such as E.Tel, Flip, ALDImobile, CMobile, Lebara and Catch Connect.
However, the cheapest option won't always mean you're going to get the best value for your money. Plans might cost less but do they offer enough data and features to match your requirements?
A good rule of thumb is to look out for deals and use the benchmark of $1 per GB to compare plans. All you need to do is divide the monthly cost by the monthly data allowance the provider is offering on its plans to find out how much each gigabyte of data will cost you.
If you've got a 5G-compatible phone, see if you've got 5G access on your mobile plan. If not, it might be time to switch. It's now easier to access 5G on a SIM only plan, with many smaller providers offering it for under $30 a month.
Mariam Gabaji
Utilities editor
Long expiry plans offer the best value for the average person who usually connects to a Wi-Fi network but might use between 10GB and 15GB of data per month. It provides a large data allowance that can be used across a year with unlimited calls and texts.
Saranga Sudarshan
Insights analyst
It pays to compare mobile plans at least once a year to make sure you're getting the best deal. Most providers increase their plan costs every 1–2 years, so the provider you've been loyal to for the last few years may no longer be serving you well.
Michelle Kwong
Mobile and broadband publisher
There's no one size fits all when it comes to choosing a SIM only plan. However, some of our top picks should be able to give you a leg up on your research.
To find out more, our team of experts selects top picks for the best SIM only plans every month, taking into account the latest promotions and discounts available on the market.
TPG was a standout this year for the budget category because it stacks up well for price and data, especially when it's running frequent promotional offers.
SpinTel and Circles.Life topped the charts this year for offering value for money. Their plans are well-priced and come with generous data allowances.
Kogan's 365-day mobile plans are some of the best around. They offer fantastic value for money and come with Wi-Fi calling and instant eSIM setup.
There are a few features to look out for when choosing a SIM only plan to help you differentiate them all. Just keep in mind that if you're not in need of any of the following features, keep it simple and get a well-priced plan with just calls, texts and data.
Also known as data banking, this allows you to bank unused data for future use. Usually providers will let you roll over your data for either your next recharge or up to a certain data limit (e.g. 200GB).
This is essentially how "unlimited data" mobile plans in Australia operate. Once you've used up your data allowance, your speeds will usually get capped to 1.5–2Mbps until your next billing cycle. This helps avoid any bill shock.
Some providers may offer unlimited international calls to selected countries on some of their plans, or alternatively they could offer a certain number of minutes or credit to call friends or family overseas.
International roaming add-ons are becoming a more frequent feature with smaller providers and not just limited to the likes of Telstra, Optus and Vodafone. They can help ease any travel jitters if you can't access a local SIM straight away.
Wi-Fi calling can be an important feature if you're having trouble with mobile network signals at your home or elsewhere indoors as it allows you to make calls over the internet.
5G is now becoming a more prominent feature on SIM only plans, from both big and smaller mobile providers including Boost Mobile, Belong and amaysim.
At the time of writing, there are 32 providers offering 5G plans on Finder and a further 5 providers offering plans with a free 5G trial.
You can check out our top picks for 5G mobile plans as a starting point to compare your options.
You can get an unlimited data SIM only plan, with prices starting at just $10 a month. However, you'll need to understand that unlimited data mobile plans come with a couple of caveats.
In Australia, most plans with unlimited data actually come with a monthly data allowance (anywhere between 2GB and 600GB), but they're considered unlimited because you won't get charged for going over this allowance.
Instead, providers will reduce your downloads speeds to around 1.5–2Mbps once you've used up your data allowance for the month.
This means you won't ever be hit with excess data charges but you'll have to put up with slow speeds until your plan renews the next month.
Only felix mobile comes close to offering a truly unlimited data plan. There's no data limit so you can use as much as you want but your speeds will be capped at 20Mbps the whole time.
The only provider that gives you the option to use your exact SIM only plan overseas in 100+ countries is Vodafone. You'll need to enable international roaming for $5 a day to do so.
Other providers may offer international roaming add-ons so you can take your plan overseas, but your call, text and data inclusions will be different.
Here's a rundown of the pros and cons of signing up to a SIM only plan so you can decide if it's right for you:
There are 3 network providers in Australia – Telstra, Optus and Vodafone. They allow smaller providers also known as mobile virtual network operators (MVNOs) to access their network in order to sell SIM only plans.
MVNOs normally have cheaper prices than the big 3. According to Finder's Consumer Sentiment Tracker, Australians spend as much as $62 a month with the big 3, but around $25 a month with a smaller telco. That's a difference of $444 over a year.
MVNOs that run on the Optus and Vodafone network have full access to their coverage. For Telstra it's slightly different.
The majority of Telstra MVNOs run on its wholesale network that reaches 98.8% of the Aussie population. Only Boost Mobile has access to full Telstra coverage which reaches 99.5% of the population.
SIM only plans from Telstra start at $62 a month for 50GB. You also get:
Optus has the second largest network in Australia. Its SIM only plans start at $49 a month for 30GB and come with:
Vodafone's SIM only plans start at $49 a month for 100GB. It offers the least amount of coverage out of the big 3 but is the cheapest of the lot. You also get:
Call us fan boys (and gals). Because nerding out on data inclusions and discount sim deals is in our DNA.
We hate sneaky fees. Paying $2 per extra megabyte? Not on our watch. We're deep in the weeds, fact-checking dozens of Aussie telco contracts to keep you aware of the hidden ts & cs.
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