What is the true lowest price for 1GB cheap SIM? The strongest cost-performance ranking revealed by actual measurement verification

For those considering a 1GB plan with budget SIMs. A 1GB/month budget SIM is ideal for people whose lives revolve around WiFi or are looking for a secondary line. Compared to major carriers, the monthly fee is significantly lower, making it a strong option for reducing fixed costs. However, since fee structures and services vary greatly among providers, many may wonder, “Where is truly the cheapest?” and “What can I do with 1GB?”

In this article, we’ve measured and verified 24 popular budget SIMs, ranking the most suitable services for operating with 1GB. We evaluate not only cost but also stability of connection speed, signal quality, ease of switching providers, and six other key points. We also explain the criteria to help you find the perfect 1GB budget SIM for your needs.

How to Choose a 1GB Budget SIM: Consideration Based on 3 Use Cases

Users operating on 1GB with budget SIMs generally fall into three main patterns. First, those mainly using email, social media, and light browsing, prioritizing the lowest possible monthly cost. Second, users who want stable, high-speed connectivity without sacrificing speed, aiming for a reliable environment with 1GB. Third, those whose data usage fluctuates month to month and need flexible billing options. The best SIM varies greatly depending on which pattern fits you.

Our actual measurements focused on speed, signal quality, initial costs, ease of data overage, support for MNP (number porting) with one-stop procedures, and more—covering all necessary factors for choosing.

Comparing Cost, Speed, and Convenience: Tips for Selecting a 1GB Budget SIM

When choosing a budget SIM, the first decision is whether the provider is an MVNO or MNO type. MVNOs lease lines from major carriers, offering lower monthly fees but potentially slower speeds during congestion. MNOs own their lines, providing more stable speeds across time. If 1GB is sufficient, prioritize low cost; if you want more stability, consider MNOs.

Also, note that initial costs differ: some charge only a service fee, others also have separate SIM issuance fees. Comparing total costs is essential.

【1st Place】LinksMate (LogicLinks): Perfect for Gamers and Video Streamers Even with 1GB

Measured score: 4.7 (Mid-January 2026)

For those who frequently play games or stream videos, LinksMate is especially convenient among 1GB SIMs. Its affordable monthly fee of 737 yen is attractive, and adding the 550-yen count-free option reduces data consumption for supported video, social media, and gaming apps to one-tenth.

After subscribing to the option, the total monthly cost is 1,287 yen—slightly higher but worth considering for avid gamers. Tests show smooth playback of high-quality videos even during busy lunch hours. Since it’s an MVNO borrowing DoCoMo’s network, speeds may slow during peak times, so keep that in mind.

After exceeding 1GB, data speeds drop to around 200kbps. Also, eSIM issuance costs 550 yen, which should be noted.

Pros: Benefits linked to gaming, high-speed during daytime, data compression options with paid add-ons

Cons: Monthly cost increases with options, eSIM fee applies, no one-stop MNP support

【2nd Place】povo (KDDI Digital Life): Best for Flexible Monthly Data Usage

Measured score: 4.69 (Early January 2026)

povo, KDDI’s online-only brand, is ideal for users whose data needs vary each month. Its unique “topping” system allows you to buy only the data you need, starting at 390 yen for 1GB. Larger packages are also available, enabling flexible operation.

For stable use of 1GB monthly, the 3GB plan (valid for 30 days) costs 990 yen, with no initial fee, and easy switching for existing users. As an MNO, speeds are stable even during congestion, and signals work well indoors and underground.

Data can be instantly purchased via app, and auto-charging for 3GB is available. No physical stores support, but chat support is accessible.

Pros: Free basic monthly fee, stable speeds via MNO, flexible topping system, no initial costs

Cons: Only online support, multiple data purchases can be cumbersome

【3rd Place】Japan Communications SIM: Cheapest 1GB Plan

Measured score: 4.66 (Mid-January 2026)

Japan Communications SIM offers the lowest price at 290 yen/month for 1GB. Ideal for light users mainly browsing email and websites, or as a secondary line.

Initial fee is 3,300 yen, similar to other providers. Calls with unlimited talk are just 1,890 yen/month. Using DoCoMo’s network, speeds may slow during congestion but remain generally manageable. Signal stability is good, even indoors or underground.

After 1GB, speeds are limited to about 200kbps, but text-heavy use remains feasible. Data can be topped up as needed, accommodating fluctuating monthly usage. Supports MNP and eSIM, making switching straightforward.

Pros: Cheapest at 290 yen/month, affordable call options, MNP support

Cons: MVNO type with potential speed drops during busy times, over 1GB requires additional purchase

【4th Place】b-mobile (Japan Communications): Flexible Pay-As-You-Go with Upper Limits

Measured score: 4.6 (Mid-January 2026)

b-mobile’s main feature is a pay-as-you-go plan. For 1GB usage, it costs 1,089 yen, slightly higher but with an upper limit set at 1GB, preventing overcharges. Suitable for users with variable data needs.

It uses SoftBank’s network, with good speeds even during busy hours, and stable signals across most areas. As an MVNO, speeds may fluctuate with congestion.

Over 1GB, speeds drop to about 200kbps, but the upper limit prevents unexpected high charges. Supports MNP and easy switching.

Pros: Flexible pay-as-you-go, upper limit prevents overcharges, MNP support

Cons: About 1,089 yen/month for 1GB, potential speed issues

【5th Place】LINEMO (SoftBank): Prioritize Speed if You Use LINE Heavily

Measured score: 4.55 (Early January 2026)

LINEMO, SoftBank’s online-only brand, is perfect for heavy LINE users. LINE data is free of charge, so calls and video chats don’t consume your data.

No 1GB plan exists; instead, a 3GB plan costs 990 yen/month. As a SoftBank MNO, speeds are very stable, allowing high-quality video streaming even during busy times. Signal quality indoors and underground is excellent.

Be aware that exceeding 3GB will automatically increase your plan cost. For light browsing and email, staying within 1GB is easy, making it a good speed-focused alternative. Supports MNP and eSIM, with no physical stores but chat support available.

Pros: LINE data free, stable SoftBank speeds, 3GB at 990 yen

Cons: No physical stores, over 3GB costs more, no 1GB plan

【6th Place】mineo (Optage): Best for Choosing Among Multiple Carrier Lines

Measured score: 4.54 (Mid-January 2026)

mineo’s biggest feature is offering lines from NTT Docomo, au, and SoftBank, allowing you to select based on your device and preferences. No need to buy a new phone.

The 1GB plan costs 1,298 yen/month—more expensive but balanced considering line options. Initial costs include a 440 yen SIM issuance fee plus the service fee. Total costs should be checked.

Despite being an MVNO, speeds on Docomo and au lines remain high even during congestion, with good signal stability. After 1GB, speeds drop to about 200kbps. There’s also an unlimited “My Soku” plan, but with limited use.

Supports MNP with one-stop procedures, ideal for those wanting to keep their current device and choose from multiple lines.

Pros: Three line options, surprisingly good speeds for MVNO, MNP support

Cons: Higher monthly fee, initial costs

【7th Place】y.u mobile (Y.U-mobile): Best for Maxing Out Data Overage Cautiously

Measured score: 4.54 (Early January 2026)

Y.U mobile’s key feature is the ability to carry over unused data forever. Unlike typical SIMs where data expires after 1-2 months, here it remains indefinitely.

No 1GB plan; instead, a 5GB plan costs 1,070 yen/month. Suitable for users with low monthly usage, who can accumulate leftover data for busier months.

Uses Docomo’s network, with speeds varying by time, but generally fast. Signal stability is good.

Initial costs include a 440 yen SIM issuance fee. No MNP support or eSIM, so switching is more involved. Usage fluctuates monthly, so if you often have leftover data, this might be worth considering.

Pros: Data rollover forever, 5GB for 1,070 yen

Cons: No 1GB plan, no MNP support, more complex switching

【8th Place】BB.excite Mobile (BB.excite): Focus on Low Cost, Speed Not Priority

Measured score: 4.54 (Mid-January 2026)

BB.excite Mobile’s “Fit Plan” charges 690 yen/month for up to 3GB. For users who only need 1GB, cheaper options exist, making this less competitive.

Uses DoCoMo and au networks, speeds slow during busy hours, especially at lunchtime. Signal stability is okay, but not suitable for speed-dependent tasks.

No MNP support; switching requires obtaining a reservation number separately. Best for those aiming to keep costs low within 3GB, but for 1GB use, other options are preferable.

Pros: Up to 3GB for 690 yen/month

Cons: Unstable speeds, slow during peak times, no MNP support

【9th Place】HIS Mobile: Cheapest if You Have WiFi at Home and Use Less Than 0.1GB

Measured score: 4.51 (Mid-January 2026)

HIS Mobile, operated by travel agency HIS, offers travel-related perks. For 1GB usage, costs 550 yen/month; if your data use is under 0.1GB, it drops to an incredible 280 yen/month.

Ideal for those with WiFi at home and minimal outside data use. Uses DoCoMo’s network, with variable speeds.

After 1GB, speeds are limited to about 200kbps. Supports MNP, easy to switch. Also offers international travel SIMs and discounts on HIS tours, appealing to travelers.

Pros: Very low cost from 280 yen/month, MNP support, travel perks

Cons: MVNO type with variable speeds, not suitable if monthly data fluctuates significantly

【10th Place】Rakuten Mobile: Unlimited Domestic Calls Included, Good for Phone-Centric Users

Measured score: 4.5 (Mid-January 2026)

Rakuten Mobile does not offer a 1GB plan; the 3GB plan costs 1,078 yen/month. Its major advantage is unlimited domestic calls included at no extra charge. Ideal for those who make frequent or long calls.

No initial fee, plus Rakuten points rewards. Currently running a “Mikitani Campaign” with bonus points.

Speeds are generally good, allowing high-quality video streaming even during congestion. Signal stability can be an issue in some underground or indoor areas. Over 3GB, charges automatically increase, so monitor usage. Supports MNP and eSIM, with ongoing improvements to coverage.

Pros: Free unlimited calls, no initial fee, points rewards

Cons: Some areas have poor signal, over 3GB costs more

Final Checklist for Choosing a 1GB Budget SIM

Choosing a budget SIM for 1GB/month depends heavily on your lifestyle. If cost is the top priority, Japan Communications SIM at 290 yen/month is unbeatable. If speed and stability matter, consider MNO options like povo or LINEMO. For fluctuating data needs, pay-as-you-go or topping systems are recommended.

Compare total costs including initial fees, understand your usage pattern, and evaluate support options. By considering these factors, you’ll find the best 1GB budget SIM tailored to your needs.