MONSTER MOBILE Real Reviews (July 2026): Monthly Plans from ¥1,980 & How to Use the 14-Day Free Trial

Verification Status: This article is based on publicly available information (no actual usage or trading by the editorial team).

At a corner table in a café, Kenta Tanaka let out a deep sigh as he stared at his open laptop. It was 2 PM at his usual coworking space. For some reason, the Wi-Fi was painfully slow today. The browser tabs just kept spinning, and even after 10 minutes, the design data upload was still incomplete. He considered switching to his phone's hotspot, but he had barely any data left for the month. He needed to do a final video review with his client, but at this rate, he wouldn't make the deadline.

At 32, working as a freelance web designer, he spent half his week at cafés and coworking spaces in Tokyo. He didn't have a fixed line at home—the hassle of installation and the two-year contract just seemed too tedious. However, the "minor stress" of unreliable free Wi-Fi and limited mobile data was slowly eating away at his work quality and peace of mind.

Then, a fellow freelancer casually mentioned, "Pocket Wi-Fi doesn't need installation, and plans start from around ¥2,000 a month." That one comment sparked Kenta's small step toward "looking into it."

MONSTER MOBILE is best suited for those who use under 100GB of data per month and prioritize low monthly fees over speed. With a 14-day free trial, its biggest strength is the ability to test it in your own daily environment before committing.

The Shocking Reality of ¥1,980/Month—What a Café Refugee Discovered About Costs

Image source: monster-mobile.jp (official website) — cited for identification of the reviewed service

When Kenta typed "cheap pocket WiFi" into the search bar, the first thing that surprised him was how affordable the monthly fees were. Among the options, one service stood out: "MONSTER MOBILE." It offered a 20GB plan starting at just ¥1,980/month (tax included). For someone who had been paying ¥2,000–3,000 each month for extra mobile data, this was a number that screamed, "Switching is cheaper."

What's more, there was no installation required. The device was provided for free as a rental, and once you applied, it could be shipped out the same day. As soon as it arrived, you could turn it on and start using WiFi immediately. The thought of escaping the small frustrations of café WiFi—"It's so slow today," or "The password changed again"—made his search fingers move faster.

MONSTER MOBILE's pricing structure is straightforward. There are three data plans: 20GB, 50GB, and 100GB, each available in two contract types: a "2-year contract" and a "no-lock-in" option. Choosing the 2-year contract lowers the monthly fee even further, and a discount campaign applies for the first six months. For example, with the 20GB plan, the first six months cost just ¥1,650 (tax included). That's roughly the price of two cups of café coffee for a month's worth of internet access. ※ Be sure to check the official website for campaign terms and discount details.

Kenta thought about how much data he actually used each month. Checking his mobile data usage, including tethering, he found it was around 40–50GB per month. In months with heavy video exchanges, it crept up a bit more. The 50GB plan would cost ¥2,530 (tax included), or ¥2,200 during the campaign period. That was definitely cheaper than his current mobile plan plus data add-ons.

"It's worth trying out at least," he thought. With MONSTER MOBILE's official site still open in a browser tab, Kenta decided to dig a little deeper.

3-Cloud Auto-Switching SIM: How MONSTER MOBILE Works and Its Real-World Performance

MONSTER MOBILE is a cloud SIM pocket WiFi service operated by NEXT Inc. Unlike conventional pocket WiFi that relies on a fixed carrier SIM, the cloud SIM system automatically selects the optimal carrier line from among the three major Japanese carriers—docomo, au, and SoftBank—via the cloud. This means that even in areas where one carrier's signal is weak, the device can seamlessly switch to another carrier's line to maintain connectivity.

This "3-carrier auto-switching" feature is a surprisingly overlooked advantage when choosing a pocket WiFi. With a standard carrier-specific pocket WiFi or a cheap SIM, you're stuck if that carrier's signal doesn't reach. With MONSTER MOBILE, if docomo is weak, it switches to au; if au is weak, it switches to SoftBank—all automatically. In many user reviews, this mechanism has been praised for its "wide coverage area."

The service offers three data plans: 20GB, 50GB, and 100GB. Each plan has a fixed monthly data allowance, and once exceeded, the speed is throttled. However, you can purchase additional data through the dedicated app. You can also upgrade to a higher-tier plan mid-contract, with a fee starting from ¥1,100 (tax included). This flexibility is useful if you find you need more data than expected after starting the service.

The device, such as the "Macaroon SE," is rented for free. There's no need to purchase it, and no rental fee is charged during the contract period. This means the only initial cost is the administrative fee of ¥3,300 (tax included). The common worry of "unexpectedly high device costs" when signing up for a pocket WiFi is completely eliminated.

MONSTER MOBILE also offers an "unlimited data plan," and with the new device "+F FS040W," users have reported stable communication and long battery life. However, since the unlimited plan comes with a higher price tag, the 50GB plan seemed like a realistic choice for Kenta, who wanted to test the waters with a capped plan first.

Comparing Plans with Other Companies — 20GB, 50GB, 100GB: Which Is the Right Choice?

To see if his gut feeling that it was "cheap" was correct, Kenta decided to line it up against other options. He set three benchmarks: WiMAX, the leading pocket WiFi service; Rakuten Mobile, which can substitute with smartphone tethering; and Happy WiFi, another cloud SIM service.

Looking at this table, Kenta felt the trade-off was between "speed" and "cost." WiMAX is fast and offers unlimited data, but the monthly fee starts at ¥4,000+, which is higher. Rakuten Mobile has the convenience of using just one smartphone, but it's not designed for pocket WiFi use, and speeds vary greatly by area. Happy WiFi is the same cloud SIM type as MONSTER MOBILE, but its data allowance was once changed from 100GB to 50GB, leaving some concern about plan stability.

On the other hand, MONSTER MOBILE clearly stands out in terms of "low monthly fees." The 20GB and 50GB plans, in particular, are competitively priced, and multiple review sites praise their affordability. While it falls short of WiMAX in speed, whether it can handle the "file uploads and downloads without stress" needed for web design work can only be tested at the actual location. That's exactly where the 14-day free trial comes in.

Kenta settled on the 50GB plan with a 2-year contract as his top candidate. The monthly fee is ¥2,530 (tax incl.), and the first 6 months are ¥2,200 (tax incl.). If he tries it for 14 days and finds it "unusable," he can cancel for free at that point. He has nothing to lose — that fact quietly pushed him forward.

The Real Story on "Connection Speed" Emerging from Reviews—The Dividing Line Between Those Who Get Stable Connections and Those Who Don't

That said, making a snap decision based solely on low prices is risky. Kenta read through multiple review sites to find out what actual users were experiencing. What emerged was a clear divide in opinions about "connection speed."

Let's start with the negative feedback. On one review site, posts like these were lined up:

The connection keeps dropping, and sometimes it won't connect for a while. In crowded areas, the speed drops to the level of a 10-year-old smartphone.

I just signed up for a new pocket Wi-Fi. Compared to my previous one, the numbers are pretty low. You can actually feel how slow it is. Time to cancel.

From around day five, it started losing signal more often, and by day seven, it was almost unusable as a device—barely any communication possible.

What these comments have in common is a drop in speed during "peak congestion" or in "specific locations." Cloud SIM automatically switches between three carriers, but in places where all carriers are congested—like train stations or large event venues—the speed inevitably slows down. There are also reports of instability due to device variations or initial defects.

On the other hand, positive reviews do exist.

MONSTER MOBILE is a service that's rated for its "low monthly cost" and "easy-to-choose data plans" among Cloud SIM pocket Wi-Fi options.

The best things were the stable connection, fast speed, and great battery life.

MONSTER MOBILE is a pocket Wi-Fi service that's popular for its variety of data plans and affordable pricing.

In particular, the combination of the unlimited plan and the new device "+F FS040W" has been reported to offer stable communication and long battery life. In other words, MONSTER MOBILE's communication quality varies greatly depending on the "device type," "usage location," and "time of day."

Kenta understood that this "fluctuation based on location and time" is exactly the key to getting the most out of the 14-day free trial. By testing it at home, your usual café, or a coworking space—places you actually use, during the times you typically use it—you can quickly see if the "slow" reviews apply to you. Conversely, signing up without a trial period is risky. Because MONSTER MOBILE lets you "try before you decide," you can enjoy the low prices with peace of mind.

Support, Cancellation Fees, and Payment Methods – What to Know Before Signing Up

After pricing and speed, Kenta’s next concern was: “What happens when I run into trouble?” Support availability, cancellation terms, and payment methods are three key points you should check beforehand to avoid regretting your decision after signing up.

First, let’s talk about support. Across several review sites, there are scattered complaints about slow support responses.

I tried calling MONSTER MOBILE support but couldn’t get through, so I sent an email instead. It wasn’t until late that night that they finally called me back.

Hard-to-reach phone lines and slow email replies are a trade-off for keeping costs low by limiting support resources. However, you can address this by “testing the support response yourself during the trial period.” Use the 14-day window to contact them and decide whether the response time is acceptable for you.

Next, cancellation fees. With MONSTER MOBILE’s 2-year contract plan, canceling during the contract term incurs a fee equal to one month’s subscription. For example, the 50GB plan would cost 2,530 yen (tax included). This isn’t particularly high compared to other pocket WiFi providers, but you should be aware that the plan assumes a two-year commitment. If you’re looking for short-term use or just want to “try it out,” you can choose the no-contract plan, which has no cancellation fees at all. The monthly fee is higher, but even the 20GB plan at 2,640 yen (tax included) remains reasonably priced.

Payment methods are limited to credit cards only. Bank transfers and debit cards are not accepted. This is a common trend among pocket WiFi services, but it can be a clear barrier for those who don’t have a credit card. Kenta uses a credit card regularly, so it wasn’t an issue for him, but if you don’t have one, MONSTER MOBILE would be off the table from the start.

Finally, overseas use is not supported. This makes it unsuitable for people who frequently travel abroad or want to use it on trips. This is a key differentiator from other cloud SIM services that do offer international coverage.

Despite these drawbacks, Kenta found them “acceptable.” The slow support can be tested during the trial period. Cancellation fees are zero if you choose the no-contract plan. He has a credit card. And he doesn’t travel overseas. So for him, the only real downside was whether the speed would be practical in his daily environment.

How the 14-Day Free Trial Works – Simulating the Process from Application to Activation

The moment of decision had arrived. Kenta opened the official MONSTER MOBILE website and simulated the application process. The steps were surprisingly simple.

Step 1: Select a plan on the official website. Choose between 20GB, 50GB, or 100GB, and decide whether to go with a 2-year contract or no contract. Kenta chose the 50GB plan with a 2-year contract: ¥2,530/month (tax included), with the first 6 months at ¥2,200/month. A banner on the screen read "14-Day Free Trial," which gave him peace of mind. First, check the latest plan details on the official website and find the data allowance that suits you.

Step 2: Fill in the application form. Name, address, contact info, and credit card details. The required fields were no different from a typical online shopping checkout and could be completed in under five minutes. No charges were incurred at this stage.

Step 3: Receive the device. Shipping is as fast as same-day delivery. At the latest, the device arrives within a few days. Since the device is provided as a free rental, you can start using it immediately after opening the box. The package contains only the device itself, a charging cable, and a simple instruction manual.

Step 4: Power on and connect. Simply enter the SSID and password displayed on the device's screen into your smartphone or laptop's Wi-Fi settings. No complicated setup is required. Kenta imagined himself connecting for the first time in his living room. The thought of being freed from the hassle of searching for a password at a café while opening his laptop—that small sense of liberation was the final push he needed to click the apply button.

Step 5: Test it out in your daily life for 14 days. At home, at a café, in a coworking space, or on a moving train—use the internet wherever and whenever you normally would, and check the speed and stability. If you find it doesn't meet your needs, simply contact them within 14 days to cancel for free. Just return the device. No costs whatsoever.

The fact that he could try it risk-free was what finally made Kendra let go of his last hesitation. If it didn't work out, he could just cancel. If it did, he would be free from internet stress for around ¥2,000 a month. Either way, he had nothing to lose. With that thought, there was no longer any reason not to click the apply button.

So, Who Is MONSTER MOBILE For? — Your Decision Guide

Based on the information above, let's clearly draw the line between who MONSTER MOBILE is "suitable for" and "not suitable for." Use this as your final decision-making tool to determine whether you, like Kenta, should "give it a try."

MONSTER MOBILE is suitable for:

• Users whose monthly data usage stays within 100GB: Plans are available with 20GB, 50GB, and 100GB data caps, so you can choose one that fits your usage. Even if you stream videos or transfer files frequently, 100GB is enough for most people.
• Users who prioritize low monthly fees over speed: Starting at ¥1,980 (tax included) for 20GB, this is among the cheapest options in the pocket WiFi industry. If you're looking to cut communication costs, there are few better choices.
• First-time pocket WiFi users: No installation required, free device rental, and a 14-day free trial — the barriers for beginners are minimized. If you've been hesitant to sign up for a fixed-line contract, this is worth considering as a first step.
• Users planning short-term use or a "trial run": With the no-contract plan, there are no cancellation fees. You can test the service during the 14-day free trial and cancel if it doesn't suit you. The risk is nearly zero.

MONSTER MOBILE is NOT suitable for:

• Users who need fast, unlimited data: Compared to high-speed services like WiMAX, cloud SIM speeds are inevitably slower. Heavy users who frequently handle large files or those unwilling to compromise on speed should look elsewhere.
• Users who need to use the service abroad: MONSTER MOBILE does not support overseas use. If you frequently travel or go on business trips abroad, choose a pocket WiFi that offers international coverage.
• Users without a credit card: The only payment method is credit card. Bank transfers and convenience store payments are not supported, so you cannot sign up without a credit card.

MONSTER MOBILE is a service that balances "low cost" with the "peace of mind of trying before committing." While there are concerns about speed, you can verify it yourself during the 14-day free trial. If it works well in your daily environment, the cost performance starting at ¥1,980/month is hard to beat.

Try it for 14 days for free. If it doesn't work out, just cancel. This "reversible first step" is MONSTER MOBILE's greatest appeal — and the action Kenta Tanaka, and you, should take first. Check the latest plan details and campaign terms on the official website, and choose the plan that fits you.

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This article is based on publicly available information as of July 2026. Rates, campaigns, and service details are subject to change without notice. For the latest details, please check the official website.

Methodology and Disclosure

Verification Method: This article is based on publicly available information verified as of . The editorial team has not personally signed up for or used the services discussed. The content is based on publicly available information (official websites, third-party reviews, and user feedback). Service details, fees, and promotions are subject to change, so please always check the official information before signing up.

Editorial Information: The editorial policy and evaluation criteria for this article are described in our Editorial Policy, and the verification procedures are outlined in our Methodology. If you find any errors, please report them via our contact form.

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Frequently Asked Questions

What is the actual internet speed like with MONSTER MOBILE?

As a cloud SIM device that automatically switches between three carriers, speeds are moderate depending on your area. It's sufficient for video streaming and web browsing, but you may notice limitations during large downloads.

What are the key points of the 14-day free trial?

During the 14-day free trial, you can cancel without paying the standard ¥3,300 (tax included) administrative fee. However, you must return the device, and be careful to avoid late return penalties.

How much is the cancellation fee?

For the 2-year contract plan, a cancellation fee applies if you cancel within the contract period. The no-contract plan has no cancellation fee. Check the official site for details.

Is credit card the only payment method?

The primary payment method is credit card. For other options, please check the official website.

Can I use MONSTER MOBILE overseas?

MONSTER MOBILE is a domestic-only service. It is not intended for international use and does not support roaming, so it cannot be used abroad.

How long does the device battery last?

The rental device 'Macaroon SE' offers about 8 hours of continuous use. The newer '+F FS040W' model is reported to have even longer battery life.

Can I change my plan during the contract?

Yes, you can. Upgrading to a higher plan costs a fee starting at ¥1,100 (tax included). You can manage the change through the dedicated app, allowing flexible data adjustments.

Which is better: MONSTER MOBILE or WiMAX?

If lower monthly cost is your priority, go with MONSTER MOBILE. If you need high-speed or unlimited data, WiMAX is more suitable. Choose based on your usage needs.

Sources

This article is based on publicly available information as of 2026-07-24.

• kaisen-hakase.com
• huchan.net
• selectra.jp
• sumai-kyokasho.net
• notes.inegales.com
• partshufu.com
• selectra.jp
• yurumalist.com
• simple-wifi.jp
• internet-hikaku.blog