Unlimited vs Fixed Data eSIM Plans: Which is Best for Japan?

Staying connected in Japan is easy thanks to eSIMs, digital SIM cards embedded in your device, that let you buy data plans online and activate them instantly without visiting a shop or swapping SIM cards. Two main types of travel eSIM plans are available:

Unlimited data eSIM plans promise unrestricted data use during your trip. These plans come with a fair usage policy (FUP) that caps high‑speed data each day (often from 500 MB to 4 GB per day). Once that threshold is reached, speeds slow significantly to 128 kbps. They are convenient but usually more expensive.
Fixed‑data eSIM plans allocate a set amount of data (e.g., 3 GB or 20 GB) with high‑speed access. When the data runs out you either lose connectivity or need to top up. These plans are cheaper and often allow tethering without restrictions .

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In this article

In this article you will learn the key differences between unlimited and fixed‑data eSIM plans, how fair usage policies and tethering rules work, how much data different activities consume, and which providers offer the best value in 2025. We draw examples from popular providers like Holafly (unlimited), Airalo (mixed plans), Nomad (mixed plans), Saily, Esimatic and eTravelSim.

Which types of eSIM plans are available in Japan?

What is the difference between unlimited and fixed‑data plans?

Unlimited plans give you high‑speed data until a daily cap is reached, after which speeds drop due to fair usage policies. For instance, Holafly’s Japan eSIM offers unlimited data but limits tethering to 500 MB of hotspot usage per day. eTravelSim’s unlimited plans provide 4 GB of high‑speed data per day and then throttle speeds to 128 kbps. These plans suit heavy users or digital nomads who need continuous connectivity but are more expensive.

Savvy’s Tip: These plans are not suitable for a heavy streaming, as the speed drops radically, which may impact the user experience.

Fixed‑data plans allocate a specific amount of data for the plan duration. Airalo’s Moshi Moshi eSIM offers 1 GB for 7 days ($4.50) up to 20 GB for 30 days ($25). Saily has fixed plans ranging from 1 GB/7 days ($3.99) to 20 GB/30 days ($24.99). Nomad’s fixed plans start at 1 GB/7 days (~£4.53) and go up to 50 GB/45 days (~£43). You can tether freely and top up if needed.

Which providers offer unlimited data eSIMs for Japan?

Holafly: Known for unlimited plans only. Prices in October 2025 start at about $3.90 for 1 day, $19.50 for 5 days, $36.90 for 10 days and $74.90 for 30 days. Holafly uses the KDDI and Softbank network with 4G/LTE coverage. Hotspot use is limited to 500 MB/day. Read full review here.

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Airalo (Moshi Moshi eSIM): Started offering unlimited plans only recently. Lower speed rate of 1 Mbps after 3 GB usage per day. Offers start at $12.50 for 3 days, 5days costs $20.50, 10 days costs $35 and 30 days is $74. Airalo uses SoftBank and KDDI networks.

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Saily: Provides unlimited options such as 10 days $34.99, 15 days $48.99 and 30 days $71.99. After a high‑speed threshold (often 5 GB per day), speeds slow to 1 Mbps.

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Nomad: Offers unlimited day passes that include a daily high‑speed quota (about 2 GB/day) followed by reduced speeds of 1 Mbps. Nomad uses KDDI and Softbank networks. Prices starts from $11 for 3 days, 5 days costs $17, and 10 days $31.
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eTravelSim: It is unclear how much data is included in their “Unlimited” plans and what fair user policy applies afterwards (Our eSIM plan provides unlimited data throughout the agreed-upon duration. However, the network provider may exercise their prerogative to implement a Fair Usage Policy to ensure optimal network performance for all users.). Prices include 7 days $19.99, 15 days $39.99 and 30 days $59.99. Tethering is not allowed on unlimited plans .
Esimatic:
- Japan eSIM: Offers 1 GB/day on the full speed. Once used the speed will drop to 1.25 Mbps. Compared to its competitors, Esimatic uses all four mobile networks in Japna (NTT Docomo, Inc., Softbank, KDDI, Rakuten Mobile). Prices include 1 day $4.49, 5 days $18.99, 10 days $39.99 and 15 days $59.99. Tethering is allowed.
- Global eSIMs: Compared to the competitors, Esimatic offers unlimited global eSIMs plans. Same as for Japan eSIMs, the customers can enjoy 1 GB/day with the full speed and then the speed is reduced to 1.25 Mbps. Prices include 1 day $18.99, 5 days $79.99 and 10 days $156.94.

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Savvy’s Tip: The prices starts per day gets cheaper the more days it’s for.

Which providers offer fixed data eSIMs for Japan?

Airalo: Offers local (Moshi Moshi eSIM), regional (Asialink eSIM) and global (Discover eSIM):
- Moshi Moshi eSIM: These eSIM plans are to be used only in Japan. Offers 1 GB/7 days ($4.50), 2 GB/15 days ($6.50), 3 GB/30 days ($8), 5 GB/30 days ($11), 10 GB/30 days ($18) and 20 GB/30 days ($25). Uses SoftBank and KDDI networks. Read full review here.
- Asialink: These eSIM plans can be used in the whole region. These list of all countries and supported mobile operators (carriers) can be found in the plan description. The prices starts at $5 for 1 GB/7days, 5 GB costs $20/30 days. The biggest plan offers 100 GB for $185/180 days.
- Discover: Global eSIMs can be used in more than 100 countries. Airalo offers two variants of Discover eSIM – one is data only, while the other includes not only data but also calls and texts. Data only eSIM starts at $9 for 1 GB/7 days. 5 GB/60 days costs $35 and 20 GB/365 days costs $66.
  Data/calls/texts eSIMs starts at $15 for 1 GB/10 mins/10 SMS/7 days. 5 GB/50 min/50 SMS/60 days would cost you $50. The biggest plan contains 20 GB/200 min/200 SMS/365 days for $89.

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Nomad: Offers local (Japan) eSIM, two regional (CN-JP-KR and APAC) eSIMs and two global (Global-EX and Global) eSIMs. Use my referral code LEOS92MM to get $3 off.
- Japan eSIM: These eSIM plans can be used in Japan only. Data only plans start with 1 GB/7 days $6, 5 GB/30 days costs $11, 10 GB/30 days $17 (sale, otherwise $22), 50 GB/45 days $57. Read full review here.
- CN-JP-KR eSIM: These eSIM plans can be used in China, Japan and South Korea. Data plans only start with 1 GB/7 days $4, 5 GB/30 days $14, 10 GB/30 days $18 (sale, otherwise $20), 20 GB/45 days costs $27 (sale, otherwise $33).
- APAC: These eSIM plans have two variants, the first can be used in 14 countries while the second one in 21 countries. The 14 countries data only plans start with 1 GB/7 days $5.50, 5 GB/30 days $17, 10 GB/30 days $20 (sale, otherwise $25), 20 GB/45 days $30 and 50 GB/45 days $72.
  The 21 countries data only plans cost 1 GB/7 days $7, 5GB/30 days $19, 10 GB/30 days $31 and 20GB/45 days $48.
- Global-EX eSIM: These eSIM plans have two variants, the first can be used in 54 countries while the second one in 82 countries. The 54 countries data only plans start with 10 GB/180 days $30, 20 GB/365 days $50, 30 GB/365 days $65 and 50 GB/365 days $125.
  The 82 countries data only plans cost 10 GB/180 days $40, 20 GB/365 days $68, 30 GB/365 days $105 and 50 GB/365 days $170.
- Global eSIM: These eSIM plans have two variants, the first can be used in 112 countries while the second one in 106 countries. The 112 countries data only plans start with 1 GB/7 days $25, 3 GB/30 days 450, 5 GB/30 days $45.
  The 106 countries data only plans cost 1 GB/7 days $12, 3 GB/30 days $26, and 5 GB/30 days $36.

Saily: Offers local (Japan) eSIM, regional (Asia and Oceania) eSIM and global (Global) eSIM:
- Japan eSIM: These eSIM plans can be used in Japan only. Data only plans start with 1 GB/7 days $3.99, 3 GB/30 days $7.99, 5 GB/30 days $10.99, 10 GB/30 days $17.99 and 20 GB/30 days $24.99.
- Asia and Oceania eSIM: These eSIM plans can be used in 19 countries within the region. Data only plans start with 1GB/7 days $4.99, 3 GB/30 days $12.49, 5 GB/30 days $19.49, 10 GB/30 days $35.99, 50 GB/90 days $95.99 and 100 GB/180 days $179.99 .
- Global eSIM: These eSIM plans can be used in 113 countries. Data only plans starts with 1 GB/7 days $8.99, 2 GB/15 days$16.49, 5 GB/60 days$33.99, 10 GB/180 days$56.99 and 20 GB/365 days $66.99.

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Esimatic:
- Japan eSIM: Provides data‑only plans with 1 GB/7 days ($3.94), 3 GB/30 days ($7.90), 5 GB/30 days ($9.90), 10 GB/30 days ($14.90), 20 GB/30 days ($25.89), 50 GB/30 days ($68.49) and 100 GB/30 days ($132.49) . It also sells day passes for 1–7 days from $4.49 to $29.99 .
- Asia eSIM: Japan is not part of the regional plans eSIM Asia.
- Global eSIM: Esimatic offers four global eSIM plans, each can be used in different number of countries. The Global eSIM plans for 106 countries include 1GB/7 days $11.98, 5 GB/30 days $48.99, 10 GB/30 days $82.89 and 20 GB/30 days $147.

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eTravelSim: Fixed plans include 1GB/7 days $4.50, 5 GB/30 days $7.99, 10 GB/30 days $12.50, 20 GB/30 days $19.99 and 50 GB/30 days $35.99. Hotspot sharing is allowed in these limited plans .

How much data do you need?

Data consumption for typical activities

Use this table to estimate how much data you might need during your trip. Remember that streaming high‑definition content or sharing hotspots/tethering will consume more data.

Activity	Approx. Data Use per hour
Messaging apps (WhatsApp, iMessage)	0.01 GB
Browsing websites	0.05 GB
Browsing social media (Instagram)	0.4 GB
Google Maps navigation	0.05 GB
Music streaming (Spotify)	0.05 GB
YouTube streaming (720p)	0.7 GB
Netflix streaming (HD)	1.0 GB
Video calls (Zoom/Teams)	0.7 GB
Hotspot tethering (emails and browsing on laptop)	0.1 GB

Savvy’s Tip: For a typical tourist who uses maps, messaging and occasional social media, 3-5 GB per week is usually sufficient. Streaming video and tethering will increase usage significantly; heavy streamers might require 10 GB or more for a week-long trip.

Factors affecting your data choice

Trip duration: For short stays, unlimited daily passes may be convenient if you plan to use more data and don’t want to monitor usage. For longer stays (two weeks or more), fixed plans with larger data allowances are often cheaper.
Usage habits: Digital nomads and content creators who need to upload or stream frequently should consider unlimited plans or large fixed-data packages (20 GB or more).
Hotspot sharing/tethering: If you plan to tether your laptop or share data with companions, check whether the plan allows hotspot/tethering. Unlimited plans often restrict tethering (e.g., Holafly limits it to 500 MB/day and eTravelSim forbids it). Fixed plans generally permit tethering freely.
Budget: Compare the price per GB. Airalo’s 20 GB plan costs $25 (~$1.25/GB), Esimatic & eTravelSIM 20 GB plan costs $25.89 (~$1.3/GB), Saily 20 GB costs $24.99 (~$1.25/GB), Nomad 20 GB costs $34 (~$1.7/GB), while Holafly’s unlimited 10-day plan costs ~£30 and may throttle after 500 MB/day; the effective cost per GB can be high for heavy users.

Pros and cons of unlimited vs fixed plans

Pros of unlimited eSIM plans

Convenient for heavy usage: Unlimited plans remove the worry of running out of data, making them ideal for digital nomads, remote workers and streamers.
Simple pricing: You pay one fee regardless of consumption.
Flexibility for uncertain usage: If you don’t know how much data you’ll need, unlimited plans provide peace of mind.

Cons of unlimited eSIM plans

Fair Usage Policy and throttling: Unlimited plans are not truly unlimited. Providers often restrict high-speed data to 500 MB to 4 GB/day and throttle speeds thereafter. This can make video streaming or file uploads frustrating.
Higher cost: Unlimited plans cost significantly more than equivalent fixed-data plans. Holafly’s 7-day plan can cost more than Airalo’s 10 GB plan which may be sufficient for many travellers.
Tethering restrictions: Many unlimited plans limit or prohibit tethering (e.g., 500 MB/day with Holafly and none on eTravelSim).

Pros of fixed‑data eSIM plans

Lower cost per GB: Fixed plans generally cost less, especially when buying 10 GB or more. Airalo’s 10 GB plan is $18 and 20 GB is $25.
Tethering allowed: You can share your connection with other devices without worrying about FUP restrictions.
Predictable usage: Great for travellers who know their data needs and want to budget accordingly.

Cons of fixed‑data eSIM plans

Risk of running out of data: You need to monitor usage and may incur extra cost or be disconnected if the data allowance is exhausted. Top-ups are available from providers like Airalo and Nomad.
Less flexible if your plans change: If you unexpectedly need more data (e.g., remote work tasks), you might have to buy additional packages.

Frequently asked questions about choosing a plan for Japan

How do fair usage policies (FUP) work?

A fair usage policy (FUP) is a limit imposed by providers on unlimited plans to ensure network stability. For example, eTravelSim’s unlimited plan offers 4 GB of high‑speed data per day and then reduces speeds to 128 kbps. Holafly and Nomad typically offer around 500 MB – 1 GB high‑speed allowances per day and throttle speeds afterwards. This means heavy streaming or video calls may become slow once you hit the limit.

Can I tether or use a hotspot with my eSIM?

Unlimited plans: Tethering is often restricted or capped. Holafly allows 500 MB of hotspot data per day. eTravelSim’s unlimited plans do not support hotspot at all .
Fixed plans: Tethering is usually permitted without extra costs. Check the provider’s terms, but Airalo, Nomad, Saily and Esimatic generally allow hotspot usage.

Do I need to provide ID or register when buying a Japan eSIM?

Most travel eSIMs do not require ID verification. You purchase online, scan a QR code and the eSIM activates when you land. Holafly sends the QR code by email and also does not require ID. Providers like eTravelSim allow automatic activation without paperwork .
However, if you plan to purchase Airalo Discover eSIM with calls and SMS, you will need an ID.

How long are eSIMs valid? Can I extend?

Plan validity depends on the provider. Airalo’s plans last 7‑30 days. Nomad’s fixed plans range from 7 days to 45 days, while Global-EX are valid up to 365 days. Saily and Esimatic have 7 day or 30 day options. eTravelSim offers 7‑30 days for unlimited plans and up to 30 days for large fixed-data plans . You can usually top up or purchase another eSIM if you need more data or a longer stay.

How do these plans compare to pocket Wi‑Fi and physical SIM cards?

The Best eSIM for Japan article explains that eSIMs are more convenient than pocket Wi‑Fi routers and physical SIM cards because they avoid rental collection/return, don’t require a local ID and let you keep your existing number. Pocket Wi‑Fi devices provide unlimited data for multiple devices but require carrying an extra device and can be costly. Local SIM cards often require registration and may not be available in advance.

Choosing the right plan: unlimited or fixed?

Use the following guidelines for selecting the right plan. Always consideryour trip length, anticipated data usage and budget.

Short trips (3-7 days) and heavy usage: If you plan to stream, navigate continuously and tether multiple devices, an unlimited day pass may be convenient despite the FUP.
Short (weekend) trips with moderate usage: Choose small fixed plans like Airalo 1 GB/7 days or Saily 1 GB/7 days. They are cost effective and avoid FUP throttling.
One-week to two-week trips: Consider 5-10 GB fixed plans from Airalo, eTravelSIM, Saily, Esimatic or Nomad. These provide enough high-speed data for most travellers. If you stream a lot, an unlimited plan like Saily 10-day with 4 GB on max speed or Holafly 10-day package may be better, but be prepared for throttling after about 500 MB/day .
Long trips (one month or more): Consider fixed plans with a long validity, for example 20 GB or 50 GB fixed plans from Nomad, Saily or Esimatic often offers the lowest cost per GB. Unlimited plans become expensive over long durations compared to the fixed one.
Digital nomads and remote workers: If you rely on constant connectivity for video calls and file uploads, unlimited plans with a generous FUP (e.g., eTravelSim’s 4 GB/day) might be worth the cost. Alternatively, consider large fixed-data plans plus a portable Wi‑Fi hotspot rental as a backup.

Conclusion

When comparing unlimited vs fixed data eSIM plans for Japan, the choice hinges on balancing cost, data needs and convenience. Unlimited plans from Holafly, Nomad, Saily and eTravelSim offer peace of mind but come with fair usage policies that limit high-speed data to 500 MB – 4 GB/day and restrict tethering. They are most suitable for heavy users or digital nomads who value unlimited access and are willing to pay more. Fixed-data plans from Airalo, Nomad, Saily, Esimatic and eTravelSim provide cheaper per-GB pricing, allow tethering and are ideal for most tourists; you simply pick a data allowance that matches your trip and usage.

Ultimately, weigh how long you will stay in Japan, how you intend to use data (maps vs video streaming) and whether you need hotspot sharing. For guidance on specific providers, check our in-depth reviews:

Best eSIM for Japan guide – compares top providers including Airalo, Holafly and Nomad.
Keep your phone number and use WhatsApp with eSIMs – a step-by-ste guide how to use your phone number while using WhatsApp with your travel eSIM
Holafly Japan eSIM review – details unlimited plans and FUP.
Nomad Japan travel eSIM review – examines fixed and unlimited day passes.
Airalo Moshi Moshi review – outlines affordable fixed-data options.
Ultimate eSIM guide – explains how eSIMs work and tips for installation.