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SIM-only mobile plans

SIM-only plans offer an easy solution to make the most of the smartphone you already own.

What is a SIM-only mobile plan?

A SIM-only mobile phone plan provides call, text and data services via a small plastic SIM card you insert into your phone. SIM-only plans do not come with a bundled handset, so if you need a new phone you should consider a contract plan instead.

SIM-only mobile phone plans operate on a post-paid basis, charging you at the end of every billing cycle based on your chosen plan and any excess calls or data you may have used. Most SIM-only plans bill on a monthly basis and include an allotment of calls, text and data that refreshes at the start of every billing cycle.


  • Month-to-month contracts give you the freedom to change plans without penalty, just make sure you let your current provider know
  • Often include international minutes for calling friends and family overseas
  • Frequent discounts and promotions to take advantage of.


  • Excess usage can lead to bill shock
  • No phone inclusion – you need to BYO.

What’s the difference between SIM-only and prepaid mobile plans?

On one level, there’s not much difference between a postpaid SIM only plan and a prepaid one. Both come with a SIM card you insert into your phone – either a regular, micro or nano SIM card depending on your device.

Where they differ is in how providers charge your usage. With a prepaid plan, you pay for your usage upfront and that’s all you get unless you buy add-on packs to cover additional usage. Postpaid SIM-only packs, on the other hand, won’t “run out” but instead charge you on a fixed basis for additional usage. These days this is most pertinent in relation to data usage, as most SIM-only plans offer unlimited calls and texts within New Zealand as standard.

The other big difference between SIM plans and prepaid plans is the level of value they offer at the same price tier. SIM-only plans typically come with more data or better call and text packages in exchange for the risk of excess usage charges. The value increases even further if you commit to a 12 or 24-month SIM-only contract.

How should I compare SIM-only plans?

  • Monthly minimum cost: The monthly cost of a SIM-only plan is the minimum you pay each month for your standard call, text and data inclusions. You do need to remember that any additional usage (such as roaming, overseas calls or excess data) incurs additional costs, but you never spend less than the minimum because the contract is structured that way.
  • Included data: Data is the key differentiator between mobile plans these days. If you spend a lot of time on Facebook or watching YouTube videos, you want to go for a plan with plenty of data. However, you should also make sure you can easily buy data top-ups in case you find yourself needing more data one month.
  • Network coverage: Plenty of telcos offer SIM-only plans, but they all use one of just three different mobile networks. Spark, Vodafone and 2degrees provide the infrastructure for every mobile provider, so it’s worth checking both coverage and expected speeds for the telco you’re looking to go with. While network coverage maps are general guides and aren’t always 100% accurate, they’re a good gauge of overall coverage that can help you decide which provider to choose.
  • International coverage: One of the key benefits of SIM-only contract plans is that they typically support global roaming across numerous countries around the world. If you travel regularly, it’s well worth looking at the relative costs for global roaming usage in your most common destinations, as this could help a given telco stand out against the competition. Even if you don’t travel, many SIM-only plans include an allotment of international minutes for calling friends and family overseas. It’s well worth checking if your destination of choice is on a reduced or even free call list with a given provider.

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