O2 is a UK mobile service, not a US domestic carrier in the evidence available here. For a US reader, the key question is whether an O2 customer’s plan covers roaming in the United States—and what it will cost. Some selected plans include US roaming, while O2 also advertises a separate daily travel option; neither arrangement applies automatically to every customer.
What does “O2 in the US” mean?
O2’s US relevance is roaming: its support information lists the United States in its Travel Inclusive Zone for eligible customers. The sources do not establish that O2 sells a US domestic mobile plan. If you are choosing a phone service for everyday use in the United States, do not treat O2 as a US carrier based on its roaming information.
For someone visiting the US with an O2 line, the practical question is which roaming terms apply to their specific plan. O2 says selected plans may include unlimited minutes, texts and data in the Travel Inclusive Zone. Check the inclusions shown in My O2 before travelling; Pay As You Go terms differ, and standard roaming rates may apply when an allowance does not cover your use. O2’s roaming support page
What can an O2 customer pay to roam in the US?
Selected-plan roaming
Some O2 plans include roaming in the US, but eligibility is plan-dependent. Do not assume the inclusion applies to every contract or Pay As You Go account. Confirm your plan’s destinations, data allowance and any limits in My O2 before departure.
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O2 Travel
O2’s separate O2 Travel offer is listed at £7 per day used for its 75-destination offer, which includes the US. The page also lists a 2Mbps roaming data speed cap. These are the terms shown on O2’s page retrieved on 8 October 2026 and may change; verify the current price, destinations and conditions before relying on them. O2 Travel
Before selecting an option, compare the total cost for the trip—not just the headline daily price—with your plan’s included roaming, expected data use and any applicable standard charges. O2’s travel page describes a charge for days used, so estimate how many days you expect to use the service and check how O2 defines a day and a chargeable use in its current terms.
Rank #2
- Please note, this device does not support E-SIM; This 4G model is compatible with all GSM networks worldwide outside of the U.S. In the US, ONLY compatible with T-Mobile and their MVNO's (Metro and Standup). It will NOT work with Verizon, Spectrum, AT&T, Total Wireless, other CDMA carriers, it is also not compatible with their MVNO (Visible, Xfinity Mobile, US Mobile, Cricket Wireless, etc).
- Compatibility with certain third-party devices and accessibility accessories, including some hearing aids, may vary depending on manufacturer support, Bluetooth protocols, software compatibility, and regional firmware limitations. For additional hearing aid compatibility information, please refer to Samsung’s official support documentation.
- 4G LTE Bands: B1/B3/B5/B7/B8/B20/B28/B38/B40/B41
- Display: Super AMOLED, 90Hz, 800 nits (HBM) | 6.7 inches, 110.2 cm2 (~86.0% screen-to-body ratio) | 1080 x 2340 pixels, 19.5:9 ratio (~385 ppi density)
- Camera: 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 2 MP, f/2.4, (macro)
How to judge O2’s service quality
A useful review needs to separate the UK service from the US roaming experience. For O2’s underlying UK service, relevant measures include value, speed, reliability, customer service, technical support and roaming value. Which? says its customer survey considers those factors, but the available excerpt from its O2 review does not provide O2’s scores, sample size or ranking. Its review is dated 28 July 2026. That evidence does not justify calling O2 the best or worst network, or assigning it a numerical rating. Which?’s O2 mobile review
For a US trip, a UK service survey cannot establish how well roaming will work at a particular American destination. The cited O2 pages state plan terms and the Travel offer’s advertised limit; they do not report real-world US coverage tests or customer-support outcomes. Check coverage and terms for your destination, and keep access to account support details before travel.
Rank #3
- Please note, this device does not support E-SIM; This 4G model is compatible with all GSM networks worldwide outside of the U.S. In the US, ONLY compatible with T-Mobile and their MVNO's (Metro and Standup). It will NOT work with other CDMA carriers, and it is also not compatible with their MVNO (Visible, Xfinity Mobile, US Mobile, Cricket Wireless, etc).
- Compatibility with certain third-party devices and accessibility accessories, including some hearing aids, may vary depending on manufacturer support, Bluetooth protocols, software compatibility, and regional firmware limitations. For additional hearing aid compatibility information, please refer to Samsung’s official support documentation.
- Camera: 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 2 MP, f/2.4, (macro). Battery: 5000 mAh, non-removable | A power adapter is NOT included.
What to check before you travel
- Identify your plan. Sign in to My O2 and confirm whether your exact plan includes the United States in its roaming allowance.
- Check your allowance and limits. Confirm what is included for minutes, texts and data, and whether any cap or fair-use condition applies to your plan.
- Compare the alternatives. If your plan does not include suitable US roaming, check O2 Travel’s current daily charge and speed cap, then compare the projected trip cost with other arrangements.
- Verify the destination and current terms. Check O2’s up-to-date roaming information for the exact destination and plan. Prices, eligible destinations and terms can change.
- Plan for a connection problem. Save O2’s support information and decide in advance how you will communicate if roaming is unavailable or unsuitable.
Is O2 worth it for a US visitor?
It may be convenient if your particular plan includes US roaming and the allowance fits your needs. If you would rely on O2 Travel instead, weigh the per-day charge and 2Mbps cap against your trip length and likely data use. The available sources do not establish a universal verdict on O2’s value or performance: the Which? survey results are not present in the cited excerpt, and no US roaming performance test is provided.
A separate US SIM or eSIM is another option to investigate if you want a local line while keeping your O2 number. It does not change O2’s roaming eligibility, charges or speed limits. If using a second line, verify that your phone is unlocked and compatible with the chosen service; the cited evidence does not establish a particular provider or device recommendation.
Quick Recap
Best Value
- GSM Unlocked: Enjoy seamless connectivity with your preferred GSM carrier. Compatible with T-Mobile, Metro PCS, AT&T, Cricket, Mint Mobile and other GSM networks. SIM card not included. For network compatibility, please check with your carrier. Note: Not compatible with CDMA networks like Verizon (Visible, Spectrum Mobile, US Mobile, Total Wireless, Straight Talk Wireless)
- Boundless Views: Enjoy immersive viewing on the spacious 6.5” HD+ display. Whether you're watching videos, browsing, or gaming, every detail comes through with stunning clarity.
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Rank #4
- Charger NOT Included, 6.7" Super AMOLED FHD+, 90Hz Refresh Rate, 385 ppi, 800 nits (HBM), 1080x2340px, 5000mAh Battery
- 128GB, 4GB RAM, microSDXC, Exynos 1330 (5nm), Octa-Core, Mali-G68 MP2 or Mali-G57 MC2 GPU
- Rear Camera: 50MP, f/1.8 (wide) + 5MP, f/2.2 (ultrawide) + 2MP, f/2.4 (macro), LED flash, panorama, HDR; Front Camera: 13MP, f/2.0, Android 14, up to 6 major Android upgrades, One UI 6.1
- 3G: HSDPA 850/900/1700(AWS)/1900/2100; 4G LTE: 1/2/3/4/5/7/12/13/14/20/25/26/28/29/30/38/39/40/41/48/66/71, 5G: 2/5/25/41/66/71/77/78 SA/NSA/Sub6/mmWave - Nano-SIM + eSIM
- US Model – Global Connectivity – Compatible with Most GSM Carriers like T-Mobile, AT&T, MetroPCS, etc. Will Also work with CDMA Carriers Such as Verizon, Straight Talk.
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