Just as in any country around the world, it is, of course, polite ( and safer) to ask a dog owner if you can pat their dog.
Same goes for asking to pat a dog in Japan.
Whether the dog is in a stroller or walking with its owner it is best to ask first. Even better? First start by complimenting the dog with a simple “KAWAIIIIIIII!”
Because of the language barrier it is best to keep it simple.
Wanchan sawatte mo ii desu ka? (May I pat your doggie?)
If the owner is fine with this (usually they are) they will respond with something like “ii desu yo” (You may!) “daijyobu desu” (that’s fine!) or “douzo” (Sure, go ahead)
And what if they gesture or verbalize no? You can politely answer “ok desu” (Ok) or “shitsureishimashita” (My apologies *for asking*)
Don’t be offended if this happens. Although it’s not common for people to say no – It is likely more to do with the owner being extremely introverted, a biting dog or an over popular dog who might not want any more attention for the day.
If you’d like to ask the dog’s name in Japanese:
Wanchan no namae wa nandesu ka? (What is your doggie’s name?)
If you love dogs I think you will also love my favourite puppy viewing spot in Tokyo. A dog washing salon in Roppongi with a big viewing window. I’ve included all the details in my Roppongi post here.
You may also like the dog park section of Yoyogi Park ( details in my Harajuku blog post here.)