Quick Answer: NTT DoCoMo vs SoftBank
NTT DoCoMo is Japan’s largest mobile carrier with over 91 million subscribers and roughly 50% mobile market share. DoCoMo offers the widest 5G coverage, the ahamo value plan at JPY 2,970 for 20 GB, and fiber through docomo Hikari.
SoftBank is Japan’s third-largest carrier with 56 million subscribers. SoftBank leads in 5G time availability and operates three brands covering all price segments - SoftBank (premium), Y!mobile (mid-tier), and LINEMO (budget at JPY 990).
Quick verdict: DoCoMo for widest 5G coverage and the d-point ecosystem. SoftBank for the cheapest entry plan (LINEMO) and wireless home internet (SoftBank Air).
Side-by-Side Comparison
The table below compares key features of Japan’s largest and third-largest mobile carriers.
| Feature | NTT DoCoMo | SoftBank |
|---|---|---|
| Parent Company | NTT Corporation | SoftBank Group Corp. |
| Subscribers | 91.9 million | 56.4 million |
| Market Share | ~50% | ~25% |
| Founded | 1991 | 2006 (Vodafone Japan acquisition) |
| Headquarters | Tokyo (Chiyoda) | Tokyo (Minato) |
| Cheapest Plan | ahamo JPY 2,970 (20 GB) | LINEMO JPY 990 (3 GB) |
| Unlimited Plan | docomo MAX JPY 7,315 | Merihari Unlimited+ JPY 7,425 |
| Budget Brand | None (ahamo is online-only) | Y!mobile, LINEMO |
| 5G Base Stations | Most locations | Highest availability time |
| Fiber Service | docomo Hikari (NTT FLET’S) | SoftBank Hikari (NTT FLET’S) |
| Wireless Home Internet | No | SoftBank Air (JPY 5,368) |
| Rewards Ecosystem | d-point | PayPay |
Test Your DoCoMo Speed | Test Your SoftBank Speed
Speed Comparison
5G Mobile Speed
Both carriers deliver competitive 5G speeds in Japan’s major cities. Performance varies by location and time of day.
NTT DoCoMo 5G:
- Download: 500-2,000 Mbps (Sub-6)
- Typical in Tokyo/Osaka: 300-800 Mbps
- Peak mmWave: up to 4.2 Gbps
- 4G LTE: 50-200 Mbps
SoftBank 5G:
- Download: 400-1,500 Mbps (Sub-6)
- Typical in Tokyo/Osaka: 300-800 Mbps
- Peak Sub-6: up to 3.4 Gbps
- 4G LTE: 50-180 Mbps
SoftBank leads in 5G time availability according to Opensignal reports. DoCoMo has more 5G base stations across more geographic areas. Peak speeds are comparable between both carriers.
Fiber Broadband Speed
Both providers use the same NTT FLET’S Hikari network for fiber.
docomo Hikari:
- 1 Gbps: JPY 5,720/month (houses), JPY 4,400/month (apartments)
- 10 Gbps: Available in select areas
- Mobile bundle discount: JPY 550-1,100 per line
SoftBank Hikari:
- 1 Gbps: JPY 5,720/month (houses)
- 10 Gbps: Available in select areas
- Mobile bundle discount: JPY 550-1,100 per line
Since both use NTT FLET’S, fiber speeds are identical. The difference is which mobile carrier you get bundle discounts with.
Winner: Tie on peak speeds. SoftBank for 5G availability time. DoCoMo for wider geographic 5G reach.
Run Speed Test Now to check your actual connection speed.
Coverage Comparison
5G Coverage
Both carriers cover all of Japan with 4G LTE. 5G coverage focuses on urban areas.
DoCoMo:
- First Japanese carrier to launch 5G (March 2020)
- More 5G base station locations nationwide
- 5G Standalone coverage in central Tokyo, Osaka, Nagoya
- Expanding to prefectural capitals across all 47 prefectures
SoftBank:
- Launched 5G in March 2020 alongside DoCoMo
- Highest 5G time availability among Japanese carriers
- Strong 5G in Tokyo, Osaka, and major cities
- 5G expanding to suburban areas
Winner: DoCoMo for geographic 5G spread. SoftBank for time spent on 5G signals.
4G LTE Coverage
Both carriers provide near-complete nationwide 4G LTE coverage. In rural prefectures (Tohoku, Shikoku), 4G remains the primary connection. Typical 4G speeds range from 30-200 Mbps.
Pricing Comparison
All prices are in JPY. Prices shown are base rates before family and payment discounts.
Mobile Plan Comparison
| Plan Type | NTT DoCoMo | SoftBank | Difference |
|---|---|---|---|
| Budget entry | ahamo JPY 2,970 (20 GB) | LINEMO JPY 990 (3 GB) | SoftBank JPY 1,980 cheaper |
| Mid-range | ahamo Large JPY 4,950 (100 GB) | Y!mobile JPY 2,365 (4 GB) | Depends on data needs |
| Unlimited | docomo MAX JPY 7,315 | Merihari Unlimited+ JPY 7,425 | DoCoMo JPY 110 cheaper |
| Light user | docomo mini (4 GB tier) | LINEMO JPY 990 (3 GB) | LINEMO is cheapest |
DoCoMo ahamo includes 5-minute free domestic calls and 20 GB for JPY 2,970. Online-only with no store support.
SoftBank LINEMO starts at JPY 990 for 3 GB with LINE data free. Also online-only. Y!mobile at JPY 2,365 adds physical store support.
Fiber Broadband Comparison
| Plan | DoCoMo Hikari | SoftBank Hikari |
|---|---|---|
| 1 Gbps (house) | JPY 5,720/month | JPY 5,720/month |
| 1 Gbps (apartment) | JPY 4,400/month | JPY 4,180/month |
| 10 Gbps | Available | Available |
| Mobile discount | JPY 550-1,100/line | JPY 550-1,100/line |
Fiber pricing is nearly identical. Choose fiber based on which mobile carrier you use to maximize bundle discounts.
SoftBank also offers SoftBank Air wireless home internet at JPY 5,368/month with no wiring needed. DoCoMo has no equivalent product.
Pros and Cons
NTT DoCoMo Advantages
- Largest carrier with 91 million subscribers and ~50% market share
- Widest 5G geographic coverage across Japan
- ahamo plan at JPY 2,970 for 20 GB with 5G is strong value
- d-point rewards ecosystem with wide retail partnerships
- docomo MAX includes Amazon Prime, DAZN, and Lemino streaming
- docomo Hikari fiber bundle saves JPY 550-1,100 per mobile line
NTT DoCoMo Disadvantages
- No plan below JPY 2,970 (SoftBank has LINEMO at JPY 990)
- ahamo has no in-store support (online only)
- docomo MAX at JPY 7,315 is expensive before discounts
- docomo Hikari shares NTT FLET’S with other providers
- Complex discount structure requires multiple conditions
SoftBank Advantages
- LINEMO at JPY 990 is one of Japan’s cheapest carrier plans
- Highest 5G time availability among Japanese carriers
- Three brands covering all price segments
- SoftBank Air wireless home internet needs no wiring
- PayPay cashback integration for shopping rewards
- Y!mobile provides in-store support at mid-tier pricing
SoftBank Disadvantages
- Merihari Unlimited+ at JPY 7,425 is the most expensive among big three
- SoftBank Hikari uses NTT FLET’S (not an independent network)
- SoftBank Air speeds can be inconsistent during peak hours
- Fewer 5G base stations than DoCoMo in some suburban areas
- LINEMO has no store support (online only)
Which Should You Choose?
The table below matches common use cases to the better carrier in Japan.
| Use Case | Recommendation | Why |
|---|---|---|
| Cheapest plan possible | SoftBank (LINEMO) | JPY 990 for 3 GB |
| Best value for 20 GB | DoCoMo (ahamo) | JPY 2,970 for 20 GB with 5G |
| In-store support needed | SoftBank (Y!mobile) | Physical stores at mid-tier price |
| Widest 5G coverage | DoCoMo | More base station locations |
| Most 5G connection time | SoftBank | Higher 5G availability |
| Streaming bundles | DoCoMo (docomo MAX) | Amazon Prime, DAZN, Lemino included |
| Wireless home internet | SoftBank | SoftBank Air at JPY 5,368 |
| Fiber bundle discount | Match to mobile | Choose fiber from your mobile carrier |
| d-point rewards user | DoCoMo | Deep d-point ecosystem |
| PayPay rewards user | SoftBank | PayPay cashback campaigns |
How to Run a Fair Speed Test
To compare DoCoMo and SoftBank mobile speeds, test in the same location and conditions.
Test steps:
- Test both SIMs in the same device at the same location (or same phone model).
- Close all background applications and downloads.
- Run 3 tests during off-peak hours and 3 during commute/evening peak.
- Ensure 5G mode is enabled in your phone settings.
- Compare download, upload, and latency together.
For fiber speed testing, connect via ethernet to the router. Both docomo Hikari and SoftBank Hikari use NTT FLET’S, so fiber speeds should be nearly identical.
Frequently Asked Questions
Which is faster, DoCoMo or SoftBank?
Both deliver similar 5G speeds of 300-800 Mbps in Tokyo and Osaka. SoftBank users report higher 5G time availability. DoCoMo has more geographic 5G coverage. For most urban users, performance is comparable. The real difference is pricing and ecosystem benefits.
Is LINEMO really on the SoftBank network?
Yes. LINEMO runs on the full SoftBank 5G and 4G LTE network. The lower price comes from online-only management with no store support. You get the same network speeds and coverage as SoftBank branded plans.
Can I use DoCoMo fiber with SoftBank mobile?
Yes, but you lose the mobile bundle discount. docomo Hikari’s discount of JPY 550-1,100 per line applies only to DoCoMo mobile plans. Using SoftBank mobile with docomo Hikari works but costs more. Match your fiber to your mobile carrier for maximum savings.
Is SoftBank Air a good substitute for fiber?
SoftBank Air at JPY 5,368 per month delivers up to 200-500 Mbps in areas with strong 5G. The main advantage is zero installation. The drawback is speed variability during peak hours, when performance may drop below 50 Mbps. Fiber is more consistent for gaming, remote work, and heavy usage.
Which carrier has better customer service?
DoCoMo has the largest retail store network through docomo shops across Japan. SoftBank offers stores through both SoftBank and Y!mobile retail locations. Both ahamo and LINEMO are online-only with no in-store support. If you want face-to-face help, DoCoMo’s standard plans or SoftBank’s Y!mobile are the options.
Summary
NTT DoCoMo is Japan’s largest carrier with 91 million subscribers and the widest 5G geographic coverage. The ahamo plan at JPY 2,970 for 20 GB offers strong value for moderate data users. docomo MAX bundles streaming services at the premium tier. Pair with docomo Hikari fiber for JPY 550-1,100 monthly discount per mobile line.
SoftBank covers all price segments with LINEMO at JPY 990, Y!mobile from JPY 2,365, and Merihari Unlimited+ for heavy users. SoftBank leads in 5G availability time and offers SoftBank Air wireless home internet for households that cannot install fiber. PayPay integration adds shopping rewards.
Choose DoCoMo for the widest 5G reach, d-point ecosystem, and streaming bundles. Choose SoftBank for the cheapest entry plan (LINEMO at JPY 990), wireless home internet, and PayPay rewards.
Test DoCoMo Speed | Test SoftBank Speed
Last Updated: February 12, 2026 Data Sources: NTT DoCoMo official website, SoftBank official website, Opensignal Japan reports, Speedtest Global Index