Saikai (西海市), located in Nagasaki Prefecture, Japan, is a city formed on April 1, 2005, through the merger of five towns on the Nishisonogi Peninsula. Known for its stunning natural landscapes, including the Saikai National Park, the city offers beautiful coastlines, scenic views, and historical sites like old whaling ports. The economy is driven by agriculture, fishing, and tourism, with key attractions such as the Kujukushima Islands and various cultural festivals enhancing its appeal.


💻 Saikai City Official Government Website

Districts and Postal Codes in Saikai

Click on the district name for the complete Japanese address, the complete English address, how to write a Japanese address, the postal code, the map location, and more.

District Postal Code
Ōshimachō Uchiurachiku 〒857-2402
Ōshimachō Ōjima 〒857-2426
Ōshimachō Ōdao 〒857-2422
Ōshimachō Kurose 〒857-2401
Ōshimachō Shioda 〒857-2424
Ōshimachō Tanōra 〒857-2425
Ōshimachō Chūōchiku 〒857-2405
Ōshimachō Terashima 〒857-2411
Ōshimachō Tōnō 〒857-2423
Ōshimachō Tokuman 〒857-2418
Ōshimachō Nakato 〒857-2421
Ōshimachō Hamaguri 〒857-2419
Ōshimachō Magome 〒857-2403
Ōshimachō Masago 〒857-2412
Ōshimachō Maze 〒857-2413
Ōshimachō Yurigaoka 〒857-2417
Ōsetochō Setoitanōragō 〒857-2301
Ōsetochō Setokashinōragō 〒857-2302
Ōsetochō Setoshitayamagō 〒857-2304
Ōsetochō Setonishihamagō 〒857-2303
Ōsetochō Setohadegawagō 〒857-2305
Ōsetochō Setohigashihamagō 〒857-2306
Ōsetochō Setofukushimagō 〒857-2307
Ōsetochō Tairauchigō 〒857-2312
Ōsetochō Tairasotogō 〒857-2311
Ōsetochō Matsushimauchigō 〒857-2531
Ōsetochō Matsushimasotogō 〒857-2532
Ōsetochō Yukinōraokūragō 〒857-2324
Ōsetochō Yukinōrakamigō 〒857-2327
Ōsetochō Yukinōrakyūragigō 〒857-2322
Ōsetochō Yukinōragōtsūgō 〒857-2323
Ōsetochō Yukinōrakōbutsugō 〒857-2321
Ōsetochō Yukinōrakomatsugō 〒857-2325
Ōsetochō Yukinōrashimogō 〒857-2326
Ōsetochō Yukinōrashimonokamagō 〒857-2328
Saikaichō Amakubogō 〒851-3507
Saikaichō Ōtaharagō 〒851-3503
Saikaichō Ōtawagō 〒851-3505
Saikaichō Omodakagō 〒851-3508
Saikaichō Kawachigō 〒851-3502
Saikaichō Kurokuchigō 〒851-3506
Saikaichō Kobagō 〒851-3504
Saikaichō Tannōgō 〒851-3501
Saikaichō Nakaurakitagō 〒857-2222
Saikaichō Nakauraminamigō 〒857-2221
Saikaichō Nanatsugamagō 〒857-2223
Saikaichō Mizunōragō 〒851-3511
Saikaichō Yokosegō 〒851-3509
Sakitochō Enoshima 〒857-3103
Sakitochō Kakinōragō 〒857-3101
Sakitochō Hirashima 〒857-3311
Sakitochō Hongō 〒857-3102
Seihichō Inōragō 〒851-3421
Seihichō Ōkushigō 〒851-3424
Seihichō Kazahayagō 〒851-3313
Seihichō Kamidakegō 〒851-3304
Seihichō Kameuragō 〒851-3303
Seihichō Komukaegō 〒851-3422
Seihichō Jikibagō 〒851-3305
Seihichō Shimotakegō 〒851-3311
Seihichō Shiranitagō 〒851-3314
Seihichō Shirosakigō 〒851-3312
Seihichō Torikagō 〒851-3306
Seihichō Nakayamagō 〒851-3302
Seihichō Hirabarugō 〒851-3315
Seihichō Hirayamagō 〒851-3425
Seihichō Miyauragō 〒851-3301
Seihichō Yakiharagō 〒851-3423

Start with the postal code, the prefecture, the city, the district, and then the number of the block and housing unit. Then end with the person’s name.
Here’s an example of how to write a Japanese address in English.
〒170-3293
Tokyo
Ginza, Chuo-ku
5-2-1
Mr. Taro Tanaka

For more information on how to write a Japanese address, see this article.


To type the Japanese postal code, first type the character code '3012.' Then press ALT + X and Japan's postal code symbol will appear.


To obtain an address in Saikai for receiving mail, sign up for a virtual address service like MailMate. MailMate provides you with a mailing address for receiving Japanese mail and packages. MailMate can also be used for company registration in Saikai, along with mail handling for Japanese properties (e.g., akiya, Airbnb, minpaku, etc.)


There are two types of PO boxes available in Saikai. The first type of PO box is provided by Saikai Post and is only available for individuals with a daily volume of mail. The second type of PO box is provided by private services with no limits on daily mail volume. Learn more about how to open a PO box in Japan.


Japan Post offers Standard Mail for regular letters and small parcels, typically delivered in 2-3 days. Express Mail speeds this up to 1-2 days. Registered Mail adds tracking and insurance, requiring a signature on delivery. Yu-Pack handles larger parcels with tracking and insurance, delivered in 1-3 days. Letter Pack provides flat-rate options for documents and small items, with tracking available. EMS is for international express delivery, offering fast service to over 120 countries. Non-Standard Mail covers items exceeding standard size and weight limits. Private couriers like Yamato Transport's Takkyubin offer domestic and international parcel delivery with tracking. Sagawa Express provides similar services, including same-day delivery and refrigerated shipping. International couriers like DHL, FedEx, and UPS offer express delivery with tracking and insurance. Specialized services include Cool TA-Q-BIN for refrigerated items, Yu-Mail for books and CDs, and Smart Letter for small documents. These options cover varying needs for speed, cost, and security. For more information on international shipping options, check out this article.


To send mail or packages from Saikai to your home country using Japan Post, costs vary based on the service type and parcel weight. For Airmail, rates range from ¥2,050 for a 1kg parcel to ¥64,850 for a 30kg parcel. Surface Mail is cheaper, starting at ¥1,800 for a 1kg parcel to ¥21,000 for a 30kg parcel, but it takes longer. Factors affecting costs include weight, distance, and chosen service. Discounted rates are available for bulk shipments. For detailed rates and more information, visit the article here.


For sending mail and packages from Saikai via Japan Post, the weight limit is 30 kg for most services. The size restrictions include a maximum combined length and girth of 3 meters (300 cm). For smaller parcels, the combined length and girth should not exceed 2 meters (200 cm). Specific dimensions and weight limits may vary depending on the service chosen (Airmail, Surface Mail, etc.). For detailed information, refer to the article here.


To print an international parcel label for Japan Post, start by creating an account on Japan Post's International Mail My Page Service. Register both sender and recipient information, then select the desired shipping service, such as EMS or Airmail. Input the shipment details, including content description, shipping date, and parcel weight. After reviewing and confirming all entered information, use the provided printer icon to print the label. For more details, refer to this article.