OSINT in Japan (日本) — Phone numbers
Before I move on to Part 3 of my Street OSINT series (Part 1 and Part 2 ) I want to focus on something else first. Something that I have come across a lot during geolocation was advertising boards and tracking down business phone numbers. One big find when geolocating in Japan is advertising boards and there are plenty of them. Whether this is an advertising board on the side of the road or just a telephone number on a shop sign they are almost guaranteed to give us an address.
First clues on advertising boards
Clues to particularly watch out for are, pictures of people or items, English words, romaji, websites, distinguishable signs and phone numbers. Pictures of people can be reversed imaged searched to potentially give us a name, English words can give us a lead on a location or a business and romaji can be easily typed into a translation service as is a romanised version of Japanese. Websites can take us directly to the business advertised, signs can tells what is around and phone numbers can be traced back to a business which can give us an exact address.

As with any language, translations should not always be taken literal, especially Japanese as it contains sophisticated characters. This is why when possible, I would recommend using the native language to navigate Google Maps. This will give more accurate results.

Yandex reverse image search ‘Text in image’ feature can provide us with the native language if the screenshot is clear enough for a recognition. A great guide by Ben is linked here for more details on how to use this Yandex feature.
Examples of Yandex Image translate (Left) and Text in image feature (down).
Landline numbers area codes
A great map of telephone area codes for Japan can be found below, this shows the first 3 digits only. Top left section of this map is Hokkaido which is actually to the north of Japan.
If we are to take one of the numbers above (0475–22–XXXX), we can instantly see the Imai Eye Hospital’s number is in Chiba (red arrow). In this instance, we are only to look at the area code, 04(7) in this case. I know this is Chiba because I can go search this manually on a map and see it says Chiba.

Landline area codes start from 01 to 09, 01 belongs and starts with Hokkaido (north of Japan but is shown on the top left on the map above), going down to 09 in Okinawa in the south so technically you would have a rough idea of the geographical location of the landline number even before looking at an area code map.
If you have an area and want to do the reverse, and find its area code number then try this.
denwam.com Use CTRL+F to search for the area you need and it should give you the area code. This website is country restricted so troubleshoot a little if the page doesn’t load right away.
Let’s break a phone number down.
0475–22–XXXX is a landline number, Japanese landline numbers are formed of 10 digits, 11 in its international format (+8147522XXXX).
- 81 = Japan’s country code
- 04 = Chiba Prefecture
- 75(2) = Mobara in Chiba
- XXXX = rest of the number
This won’t really be shown on advertising boards but if you see it, Japan’s country code is +81, area code will always start with a 0 followed by another digit, in this case 4 which belongs to Chiba, 75(2) belongs to Mobara in Chiba and the rest is the individual phone number. I put 2 in brackets as Mobara has multiple area codes.
We’ll never really have to remember all this as Areaphones.com/Japan breaks numbers down with its reverse phone lookup option. It won’t tell us whose number it is (not this website anyway) but it can tell us where this landline is coming from. Just remember to write the number in its international format. If this is a mobile number it will only tell you it’s a mobile number and nothing else.
Another great phone number breakdown is searchpeopledirectory.com. This offers an instant area find.

Mobile phones and toll free numbers
Other numbers we might see advertised are mobile phone numbers, they can be distinguished by the first 3 digits which can either be 070, 080 or 090 and are 11 digits long. denwa-bangou.com can give brief insight into where a mobile number comes from geographically simply by checking the carrier name.
For toll free numbers I quickly check that what I have found is valid. Via numverify.com I see 0120–041–XXX (House Do advert) is a toll free number and is a valid number in Japan. This website requires signup as of 2023. Toll free numbers in Japan start with 0120 (or 0800) and are 10 digits long. They are used by businesses so the customer doesn’t pay for calling them.
Full numbers and partial numbers
Landline phone numbers is what you will find on most advertising boards and are the ones that can give us an address.
Full numbers
Option 1
Full numbers are the easiest to search as Telnavi (country restricted website) and jpnumber are great at giving you an exact location of the business.



Telnavi is a great Japanese resource, it can search all kinds of numbers, landlines, mobiles, IPs and toll free numbers. It is for landlines that I mainly use this for and is the most accurate for me on those occasions.
Telnavi gives me the exact address of this shop, its nearest train station, its name in Japanese and a Google Map of its exact location. Having this Google map link at the bottom has been incredibly helpful as pasting translations into Google Maps will not be as accurate as when dealing with the native language.
Option 2
Input the 10 digit phone number after the ‘/’ here: 24u.jp/0123456789 . This is a great website for finding businesses in Japan, especially as it sometimes gives you their business corporate number and a name of someone who looks after the business. Equally, if you have a business corporate number this website can find you the business name simply by typing the number after the ‘/’ .
Partial numbers
Option 1
The reverse image search of the screenshot below (via the Yandex text in image feature) gave me the name of the shop like below in the Japanese language. Paste the Japanese with the partial phone number in Telnavi or jpnumber. For example: ビ ジ ネ ス ス カ イ シ ー ホ テ ル 23–2400 and it will match the partial number to numbers already on their system with the name of the place we already have. We now have an exact address.


Option 2
Paste the Japanese name of the above Hotel into itp.ne.jp and it will try to find it. I usually get a match giving me an address, a map and a phone number.
itp.ne.jp is a business search website where by simply adding a business name it should find its exact location and a phone number. This is useful when we find businesses with no phone number or partial phone numbers.
Be mindful that when you copy and paste the Japanese translation from Yandex in particular, take out the spaces between the characters as Yandex will add those in automatically and itp.ne.jp will not recognise the text if spaces are in.
Resources used worldwide that work for Japan too
numlookup.com can give us a carrier name and a prefecture. The carrier name can give us an idea which part of Japan the number is based in, for example ‘NTT — West/East Japan’.
Searchyellowdirectory.com gives you the area code the number is for.
sync.me works well too in giving us a region and a prefecture.
emobiletracker.com gives us a region and a carrier name amongst other data.
This was just a short guide on phone numbers in Japan. If you think something is incorrect or you disagree please drop me a message.
Are you playing a world Geoguessr challenge? Then try geotips.net for tips and tricks on every country on Geoguessr.