Prices shown are in AUD and may vary. Check the latest prices at travelren.com.
Optus Roaming Japan 2026: $5/day Day Pass vs eSIM
Yes, Optus works in Japan. The International Day Pass auto-activates at AUD$5 per day (Japan is Zone 1) on the SoftBank network, giving you calls, texts, and 2GB of data per day. For a standard 14-night Japan trip that's AUD$70. A Travelren Japan eSIM for the same trip costs from AUD$12.50. Optus is cheaper than Telstra in Japan — but the eSIM is still cheaper from day 3 onward.
Travelren sells Japan eSIM plans, so this comparison has stakes. We've included the exact break-even point and the genuine cases where sticking with Optus is the right call.
The quick answer
- Optus International Day Pass in Japan: AUD$5/day for unlimited calls + texts + 2GB data, auto-activates, charged per usage day.
- Travelren Japan eSIM, 3GB / 30 days: approximately AUD$12.50
- Break-even: Day Pass is cheaper for 1 to 2 nights. From day 3 onward (AUD$15 in Day Pass charges) the eSIM at ~AUD$12.50 is cheaper, and the gap grows every day.
How Optus actually works in Japan
Optus roams primarily on SoftBank in Japan, which has excellent 5G and 4G LTE coverage across Tokyo, Osaka, Kyoto, Hiroshima, and Fukuoka. NTT Docomo has slightly stronger rural coverage in mountain areas, but for the destinations most Australian travellers visit, SoftBank is perfectly adequate.
Day Pass auto-activates on first use. Optus sends an SMS confirming the AUD$5 charge for that day. Days you don't use the network aren't billed — but background syncs and push notifications count as use. Turn mobile data off on your Optus SIM before midnight if you don't want the Day Pass to activate on a given day.
Optus International Day Pass detail
- AUD$5 per 24-hour usage window from first activation (Zone 1 rate)
- Includes unlimited standard national and international calls and SMS
- 2GB of data per day; throttles to 1Mbps after the cap (no extra charge, no cut-off)
- Available on most Optus postpaid plans including Choice Plus and My Plan — verify in the My Optus app
- Charged in AUD regardless of the yen exchange rate
What a Japan eSIM costs for the same trip
Travelren Japan eSIM plans (AUD as of May 2026):
- 1GB / 7 days: approximately AUD$4.60 — suited to a short city break with hotel Wi-Fi
- 3GB / 30 days: approximately AUD$12.50 — comfortable for one week of moderate use
- 5GB / 30 days: approximately AUD$20 — two weeks with daily maps, photos, and FaceTime home
- 10GB / 30 days: approximately AUD$28 — heavy use, tethering, daily video calls
- Unlimited / 30 days: approximately AUD$48 — never think about your data budget again
Browse the full Japan eSIM range.
Break-even math
| Trip length | Optus Day Pass ($5/day) | Travelren eSIM | Cheaper option |
|---|---|---|---|
| 1 night (short stopover) | AUD$5 | ~AUD$4.60 (1GB/7d) | Almost equal — eSIM ~AUD$0.40 cheaper |
| 2 nights | AUD$10 | ~AUD$12.50 (3GB/30d) | Day Pass cheaper by AUD$2.50 |
| 3 nights | AUD$15 | ~AUD$12.50 (3GB/30d) | eSIM saves AUD$2.50 |
| 1 week | AUD$35 | ~AUD$12.50 (3GB/30d) | eSIM saves AUD$22.50 |
| 10 nights | AUD$50 | ~AUD$20 (5GB/30d) | eSIM saves AUD$30 |
| 14 nights (standard Japan trip) | AUD$70 | ~AUD$28 (10GB/30d) | eSIM saves AUD$42 |
| 21 days (Japan circuit) | AUD$105 | ~AUD$48 (Unlimited/30d) | eSIM saves AUD$57 |
Prices approximate. Check travelren.com/destinations/japan/ for current pricing.
When Optus Day Pass genuinely wins
- Short stopovers of 1 to 2 nights — at AUD$5 to $10, the Day Pass undercuts most eSIM plans for very short stays. A single night in Tokyo is the only scenario where Day Pass clearly wins.
- Your phone doesn't support eSIM — check the device check page for compatibility.
- You make a lot of standard voice calls on your Australian number — Day Pass includes unlimited calls; the eSIM is data-only.
- Corporate expense account covers it — if your employer reimburses Optus roaming, Day Pass costs you nothing out of pocket.
- Single-SIM phone and you need your Australian number for 2FA — dual-SIM devices avoid this entirely (eSIM for data, Optus SIM for calls and texts simultaneously).
When the eSIM is the better call
- Any trip of 3 nights or longer — crossover is day 3; the saving grows from there.
- You want more than 2GB — Optus Day Pass throttles at 2GB daily. Japan's transit apps, offline maps (Google Maps Japan is heavy), and regular video calls can hit that quickly on a busy day.
- You're travelling with family — four people on a 14-night trip is AUD$280 in Day Pass charges; four eSIMs is approximately AUD$112.
- You want the dual-SIM setup — eSIM for data + Optus physical SIM for calls and texts, data roaming off on Optus. No Day Pass charges, Australian number stays active.
How to run dual SIM in Japan
Buy the Japan eSIM before you fly
Choose a plan at travelren.com/destinations/japan/. You'll receive a QR code by email within minutes.
Install the eSIM on Wi-Fi at home
iPhone: Settings → Mobile Data → Add eSIM → Use QR Code.
Android: Settings → Connections → SIM Manager → Add eSIM → Scan QR code.
Install before you leave Australia — you need Wi-Fi for the initial download.
Turn off data roaming on your Optus SIM
iPhone: Settings → Mobile Data → your Optus line → Data Roaming → off.
Android: Settings → Connections → SIM Manager → your Optus SIM → Data Roaming → off.
This stops the Day Pass from activating. Without this step, Optus charges $5 even when the eSIM is doing all the work.
Set the eSIM as your mobile data source
When prompted which SIM to use for mobile data, select the Japan eSIM. Your Optus SIM handles calls and texts; the eSIM handles data. Both lines work simultaneously.
Not all phones support eSIM. iPhones bought in mainland China and some older Android models don't have eSIM hardware. Use the device check tool to confirm your phone is compatible before purchasing.
Common questions
Does Optus work on the Shinkansen?
Yes. SoftBank has strong 4G LTE coverage along the main Shinkansen corridors — Tokyo to Nagoya, Osaka, and Hiroshima. There are brief tunnel blackouts of a few seconds, but signal returns immediately. For the Sanyo Shinkansen west of Hiroshima and Kyushu Shinkansen, coverage is slightly patchier in rural sections but adequate for most passengers. A Japan eSIM on equivalent networks performs identically.
Do I need a Japanese SIM to use Suica?
No. Suica and Pasmo via Apple Wallet or Google Wallet work with your Australian bank card — no Japanese phone number or local SIM required. You need data to top up via the app, but any connection (Day Pass or eSIM) handles that. Adding Suica to Apple Wallet at Narita or Haneda airport works on any data connection.
Is coverage in Tokyo, Osaka, and Kyoto reliable?
Yes. SoftBank (Optus's roaming partner) has full 5G and 4G LTE coverage across all major cities and tourist areas. Coverage in mountain areas like Nikko, the Japanese Alps, and rural Kyushu can drop to 3G, but the major tourist circuit is well-covered. A Japan eSIM on SoftBank or KDDI au performs identically to Optus Day Pass for city travel.
Will iMessage and WhatsApp still work?
Yes. Both are registered to your Apple ID and phone number, not the SIM. Any active data connection — Day Pass or eSIM — lets iMessage and WhatsApp work normally on your Australian number.
Does the $5/day rate apply to all Optus plans?
The AUD$5/day International Day Pass is included on most Optus postpaid plans. Check the My Optus app under International Roaming before you travel. Some older or entry-level plans may have different rates — verify before you fly rather than on arrival.
The bottom line
Optus at AUD$5/day in Japan is significantly cheaper than Telstra at AUD$10/day, which makes the comparison with an eSIM much closer. Day Pass wins for 1 to 2 nights; the eSIM wins from day 3 onward. For a standard 14-night Japan trip, the eSIM saves AUD$42.
The optimal setup: Japan eSIM for data (from AUD$12.50), Optus SIM for calls and texts with data roaming switched off. Total cost approximately AUD$12.50 to $28 depending on your data needs — versus AUD$70 if you leave the Day Pass running for two weeks.
Heading to Japan for more than 2 nights? The eSIM wins.
From AUD$4.60. SoftBank and KDDI au networks. Instant QR delivery.
Browse Japan eSIM plans