What to look out for with Sim Only?

More and more Dutch people are switching to a Sim Only contract, but choosing the right provider is not always easy in reality. Recent research by the Autoriteit Consument & Markt (ACM) shows that four in ten consumers have difficulty comparing mobile contracts. In this article, we will tell you exactly what to look out for when choosing a Sim Only contract, so that you can choose the right provider and bundle for your situation.

What is Sim Only?

Simply put, a Sim Only contract is a mobile contract without a phone. This means you use your own device and only pay monthly for your call minutes, text messages, and data. The big advantage? You are not tied to high device payments and therefore have more freedom to switch or adjust your bundle.

Important selection criteria

Network coverage and speed

The quality of the network determines whether you can make calls without interference and whether your internet works quickly. In the Netherlands, we have three different network providers with their own networks: KPN, Vodafone, and Odido. All three networks have their own characteristics. For example, one scores better on reliability and another on speed. However, the most important thing to check is the coverage at your location. Without good coverage, a fast network or reliability is of no use. Therefore, always check your provider's coverage map to see if the network in your region is strong enough. Does your region fall within all three coverage maps? Then look at the difference in speed and reliability.

Customer service and reviews

A low price is nice, but it often means you compromise on service. Good customer service can save you a lot of frustration in some situations. So read online customer reviews or watch our Provider Review videos. In these videos, we discuss the pros and cons of each provider. This way, you know how providers score on accessibility, clarity, and service.

Price, bundles, and extras

Don't just compare the monthly price, but also look at what you get for it. For example, some providers offer unlimited calls or extra data when you switch. Also, keep an eye out for temporary promotions, such as double data or discounts in the first few months.

 

Curious about the cheapest Sim Only contract? Check it out here

5G, VoLTE, and actual speeds

More and more providers are offering 5G—faster internet with less latency. This is useful if you stream a lot or work from the cloud. With VoLTE (calling via 4G), you also get better sound quality during calls. This is an extra feature that is also being offered more and more often.

Switching to Sim Only: step-by-step plan

Step 1: Choose the right provider

Start by comparing providers. Pay attention to coverage quality, price, bundle size, and customer service. Use our Comparison page or ask Welli for help. Our smart AI will find the best deal for you in no time.

Step 2: Request number portability

Have you made your choice? Great! When you sign up for your new Sim Only contract, indicate whether you want to keep your current number. Your new provider will take care of the rest.

Step 3: Activate on the transfer date

As soon as your new SIM card arrives, you will receive an activation date. On that day, your old contract will automatically end and the new one will start. Insert the SIM card into your phone and you're ready to call and surf. 

Advantages of switching

  • Lower monthly costs: take advantage of welcome offers.

  • Better coverage: switch to a stronger network.

  • Flexibility: choose monthly cancellable bundles.

Best providers and networks (2025)

Most Sim Only providers use the networks of KPN, Vodafone, or Odido. This says something about the coverage of these providers, but it doesn't say anything about the speed of your bundle. So pay close attention to the characteristics of each provider! 

KPN, Vodafone, and Odido: network overview

Although these three networks offer almost complete coverage nationwide, it is still wise to check the coverage in your region. Vodafone often scores highly in urban areas, while KPN performs slightly better in rural areas compared to other providers.

Budget vs. unlimited contracts

Do you use little data? Then choose a small bundle and save a lot. Do you stream a lot or use your mobile for work? Then an unlimited internet contract is worthwhile.

 

Read more about unlimited internet

Speeds and 5G availability

5G is now available almost everywhere. However, the speed, download speed, and upload speed vary per provider. It is therefore always worthwhile to compare current speeds. Consult our smart AI Welli for this.

Common mistakes when choosing Sim Only

Choosing the wrong bundle size

Bundles that are too small result in high out-of-bundle costs, while bundles that are too large are a waste of money. Check your current usage in your phone settings or via your current provider.

Contract duration and flexibility

A 2-year contract is often the cheapest option, but a monthly contract offers the most freedom. Therefore, carefully consider what is more important to you: flexibility or saving money.

Roaming and use abroad

Within the EU, you can usually make calls and use the internet at no extra cost. Outside the EU, different rates apply. So check your provider's roaming conditions in advance or check our article: Roaming on or off outside Europe?

Conclusion: choose wisely with Sim Only

A Sim Only contract is ideal if you want more control over your costs and don't want to be tied to a device. But you can only make the best choice if you look beyond the price. Pay close attention to the network coverage, bundle size, flexibility, and customer service of your contract.

 

In short: take the time to compare, read other users' experiences, and decide what is really important to you. That way, you will find a Sim Only contract that suits your usage and your wallet.

 

Don't feel like figuring it all out yourself? Let Welli help you. All your questions will be answered within 2 minutes.