2025-06-05 · undefined · Regional Info
Japan and Korea together represent Asia's most technically demanding IoT markets. NTT Docomo, KDDI, and SoftBank cover Japan with LTE-M launching on Docomo in 2025; SK Telecom, KT, and LG U+ blanket Korea with nationwide LTE-M and NB-IoT. But neither market accepts CE or FCC certification alone. Japan requires MIC/TELEC Radio Law certification with a domestic representative. Korea requires dual KC Safety + KCC RF certification. Both regimes changed materially in 2025.
Japan has 2.1 million licensed cellular IoT connections. Korea has 1.4 million. Small numbers compared to China's 400 million. But per-device data revenue in Japan averages ¥380/month ($2.50) — roughly 4× the global IoT ARPU. These are high-value markets where certification failure means months of delay, not a form rejection.
NTT Docomo operates Japan's largest cellular network with LTE on B1 (2100 MHz), B3 (1800 MHz), B19 (800 MHz), B26 (850 MHz), and B28 (700 MHz). Docomo launched LTE-M (Cat-M1) commercially in 2025, joining its existing NB-IoT service on B19. LTE-M coverage expands from metropolitan Tokyo/Osaka outward. KDDI (au) operates LTE on B1, B3, B18 (800 MHz), B26, B28, and B41 (TD 2500 MHz). KDDI targets automotive telematics and industrial monitoring. SoftBank runs LTE on B1, B3, B8 (900 MHz), B28, B41. SoftBank acquired Arm in 2016 and has invested disproportionately in IoT infrastructure — its Cat-M1 and NB-IoT networks are the most mature among Japanese carriers, with coverage extending to suburban and rural prefectures. Rakuten Mobile operates a greenfield virtualized 4G/5G network on B3 and n77 with API-first connectivity management.
B18 (800 MHz lower, KDDI) and B19 (800 MHz upper, Docomo) are Japan-specific LTE bands that do not exist elsewhere. B26 (850 MHz) is used by both Docomo and KDDI. The practical minimum band set for a Japan-capable module is B1/3/8/18/19/26. Modules sold as "global" variants frequently omit B18 and B19 — rendering them useless on two of Japan's three major networks.
SK Telecom (SKT) operates LTE on B1, B3, B5 (850 MHz), B7 (2600 MHz), B8. SKT launched nationwide LTE-M in 2018 and NB-IoT in 2017. KT operates LTE on B1, B3, B5, B7, B8 with nationwide LTE-M and NB-IoT — over 1 million smart meters deployed on its NB-IoT network. LG U+ runs LTE on B1, B5, B7, B8. All three Korean carriers operate 5G NR on n78 (3.5 GHz). For IoT modules, B1/3/5/7/8 covers all three Korean operators.
Korea's LTE bands are globally standard. B5 (850 MHz) provides the best deep-indoor propagation across all three carriers. B7 (2600 MHz) is the capacity layer. LTE-M operates on B5 and B3; NB-IoT uses B5 guard bands. A module supporting B1/3/5/7/8 covers all three Korean carriers plus most European and Asian networks.
Japan operates a dual certification system under the Ministry of Internal Affairs and Communications (MIC). TELEC certification (R mark) covers the Radio Law. Required for every device that transmits RF. JATE certification (T mark) covers the Telecommunications Business Law — required only for devices connecting to Japan's public telephone network. Most data-only IoT devices do NOT need JATE. This is the single most common overspend in Japan IoT certification: applying for JATE when unnecessary, adding 4-6 weeks and $3,000-5,000.
Key TELEC requirements 2025: Japanese domestic representative mandatory (legally registered entity). Technical documents in Japanese. Test reports from MIC-recognized labs only (SGS Japan, JATEC, VCCI) — FCC and CE not accepted. Label must be permanently affixed (laser etching or screen printing). Cybersecurity Measures Conformity Declaration mandatory for IoT devices since 2025. OTA firmware updates changing RF parameters invalidate certificate. No fixed expiry but void on hardware/firmware/label changes.
KCC RF certification covers RF characteristics, frequency bands, power limits, spurious emissions. KC Safety certification covers electrical safety, EMC (KN 32 replacing KN 22), and cybersecurity (KN 18031 for network-connected IoT). 83% of wireless devices detained at Korean customs in 2025 were missing one certification. Self-compliance pathway available for ≤10 mW devices (BLE 5.3+, NFC). KN 18031 cybersecurity mandatory: TLS 1.3, WPA3, penetration testing. 5 GHz gap: 5350-5460 MHz is military-exclusive. KC mark ≥5 mm height, permanent.
Roaming into Japan/Korea is technically possible but economically poor: roaming data costs €0.50-1.50/GB wholesale vs local rates 5-15× lower. Latency: roaming hairpins through home PLMN adding 80-200 ms vs <20 ms local. For <1 MB/month devices, roaming works. For >10 MB/month, local eUICC profiles pay back within months. For latency-sensitive applications, roaming is not viable.
1. Shipping with only FCC/CE. Neither country accepts them. 2. Assuming pre-certified modules eliminate device-level testing. 3. Missing domestic representative. 4. Missing B18/B19 bands. 5. Applying for JATE when device is data-only. 6. Using adhesive labels instead of permanent marking. 7. Overlooking Korea's 5 GHz military gap (5350-5460 MHz).