Best MVNOs on Three Network UK (2025 Guide)

Choosing an MVNO (Mobile Virtual Network Operator) that runs on the Three network can be a smart move if you want good 4G/5G coverage, flexible plans, and lower costs. Over the years, I’ve tested and compared several Three-based MVNOs — SIM-only and contract — and asked friends and colleagues who use them in different parts of the UK (city, suburbs, rural) to see how real-world coverage and value actually stack up.

Here’s a breakdown of the top MVNOs on Three’s UK network, what makes each one great, and which provider might suit you depending on how and where you use your phone.

What Does “On Three’s Network” Mean?

When an MVNO uses Three’s network, it means they lease Three’s infrastructure (masts, 4G/5G bandwidth, etc.) rather than building their own. According to Three’s own wholesale site, many of their MVNO partners get full access to Three’s modern network features, including 5G, VoLTE, and Wi-Fi calling. :contentReference[oaicite:0]{index=0}

Thanks to this setup, you often get very similar coverage and speeds compared to someone on Three itself — but usually at a lower cost or with more flexible plan terms.

Top MVNOs on Three Network in the UK (2025)

1. iD Mobile

Probably the most well-known MVNO on Three’s network, iD Mobile is owned by Currys and offers a good mix of SIM-only and handset plans. :contentReference[oaicite:1]{index=1}

Network access: Full Three network including 4G and 5G. :contentReference[oaicite:2]{index=2}
Plan flexibility: Offers 1-, 12-, and 24-month SIM-only contracts, which is handy if you don’t want to commit long term. :contentReference[oaicite:3]{index=3}
Standout features: Data rollover — unused data gets carried forward. :contentReference[oaicite:4]{index=4}
Roaming: Some plans include roaming benefits. :contentReference[oaicite:5]{index=5}

From my experience, iD’s plans are very well balanced: you pay for what you use, with no hidden bits, and the 5G performance is solid in most towns and cities. If you're on a budget or want a SIM-only plan, it’s one of the most reliable choices on Three.

2. SMARTY

SMARTY is closely linked to Three (in fact it's owned by the same parent company), and is designed to be a super-lean, no-nonsense SIM-only provider. :contentReference[oaicite:6]{index=6}

30-day rolling plans: Great flexibility — you can cancel or change every month.
Refund for unused data: If you don’t use all your data, they refund you for what you didn’t use. It’s one of the few MVNOs that does this in a meaningful way.
Access to Three’s newer tech: Because it's closely integrated, you still benefit from Three's upgrades. :contentReference[oaicite:7]{index=7}

I used SMARTY for a few months during a move between flats: I started with a high-data plan, dropped down when I was less busy, and didn’t feel locked in. Coverage remained very good and I rarely saw performance drop-off.

3. Superdrug Mobile

Superdrug, the high-street pharmacy chain, also operates a mobile service on Three’s network. According to regulatory data, it's a “light” MVNO on 3UK. :contentReference[oaicite:8]{index=8}

Low-cost SIM-only: Generally aimed at budget-conscious users.
Reliable coverage: Because it's on Three, you’re not sacrificing signal for price.
Simple plans: It doesn’t try to be ultra flashy — straightforward data / minutes / texts.

If you already visit Superdrug shops or prefer a straightforward, reliable SIM, this is an appealing choice for Three-based service.

4. Gamma Mobile (Business-Focused)

Three’s wholesale site mentions Gamma as a partner for business MVNOs. :contentReference[oaicite:9]{index=9} Gamma Mobile is less known among regular consumers but is strong for companies or freelancers who need business-level reliability plus Three’s infrastructure.

Business expertise: Gamma has over 20 years in B2B mobile, making them experienced in supporting business mobile needs. :contentReference[oaicite:10]{index=10}
Network parity: According to Three, their MVNOs get the same 4G / 5G access via a “light MVNO” solution. :contentReference[oaicite:11]{index=11}
Scalable plans: Good for small businesses wanting to roll out several SIMs or manage mobile costs carefully.

If you run a small business or need several lines for a team, Gamma Mobile could be a smart, cost-effective way to tap into Three’s network without paying for premium business tariffs.

5. (Honest Mobile – Emerging Option)

Honest Mobile is often mentioned in MVNO lists as a budget provider that uses Three’s infrastructure. While it's smaller compared to iD or SMARTY, it’s gradually growing in popularity for its transparency and low-cost SIM-only options. :contentReference[oaicite:12]{index=12}

Fair plans: Honest prides itself on no hidden fees and straightforward pricing.
Good for basic use: Ideal if you need solid data + calls + texts, without extras.
Future upgrades: Always worth watching—they may expand their plan options as they scale.

I recommended Honest to a friend who didn’t need much data but wanted a reliable SIM. He reported good service and consistent connectivity on Three masts in his area.

Why These Three-Based MVNOs Are Worth Considering in 2025

Strong 5G and 4G coverage: Since they use Three’s masts, you’re unlikely to sacrifice coverage for cost. Three’s broad UK network remains competitive. :contentReference[oaicite:13]{index=13}
Good integration: Three’s “light MVNO” offering gives MVNOs access to important network features like LTE+, VoLTE, and Wi-Fi calling. :contentReference[oaicite:14]{index=14}
Improving infrastructure: With the recent Vodafone–Three merger, there's a big push to improve 4G/5G coverage via shared sites (MOCN rollout), which will benefit many MVNO customers. :contentReference[oaicite:15]{index=15}
Flexible plans: Many of these MVNOs offer 30-day rolling SIMs or a variety of contract lengths, making them more user-friendly than many traditional plans.
Value for money: Since they don’t need to fund their own network infrastructure, MVNOs can offer very competitive pricing. For example, iD Mobile and SMARTY often appear on “best value” MVNO lists. :contentReference[oaicite:16]{index=16}

Drawbacks to Be Aware Of

Potential for deprioritisation: During very heavy network usage, MVNO traffic might be deprioritised compared to Three’s own customers (common with virtual networks, though real-world impact varies).
Fewer perks: Unlike major networks, many MVNOs don’t bundle generous entertainment bonuses or full phone bundles — what you save is often in service simplicity.
Smaller support teams: Customer service may not be as large or as fast as big network providers.
Plan changes: Some MVNOs change their plan offers regularly, so what’s good today may shift; always check current deals.

How to Choose the Right Three-Based MVNO for You

Here are some practical steps I suggest, based on my experience when I switched MVNOs:

Check coverage in your area: Use Three’s coverage map + your potential MVNO’s site to confirm signal strength where you live, work, or travel most often.
Decide your plan style: Do you prefer no contracts? Go for SMARTY or Honest. Need a long-term SIM deal? iD might offer more stable rates.
Estimate data usage: If you stream or hotspot, look for high-data or unlimited plans. For casual browsing or calls, lighter packages may suffice.
Watch for promos: MVNOs frequently run offers (e.g., sign-up discounts), so check comparison sites to find the best current deal.
Read the small print: Especially around rollover, roaming, or speed restrictions — not all plans are the same.

Conclusion

If you want to tap into Three’s network without paying for Three itself, MVNOs like iD Mobile, SMARTY, Superdrug Mobile, Gamma Mobile, and Honest Mobile are among the best options. They combine good coverage, flexible plans, and competitive pricing — and with the ongoing network upgrades, their service is only going to get better. Choose the one that fits how you use your phone, double-check coverage in your area, and you could save a lot while still enjoying a reliable mobile connection.

best MVNOs on Three network UK