Question 1

Where is 25 porticos?

Accepted Answer

25 porticos is in Minato, Tokyo, Japan. You can see its exact position from the map coordinates and the Street View link.

Question 2

Which scene of Negative Positive Angler does 25 porticos appear in?

Accepted Answer

25 porticos appears in EP3 of Negative Positive Angler.

Question 3

Can I visit 25 porticos?

Accepted Answer

Yes. 25 porticos is a real place you can visit. Check what it looks like on Street View before you go.

Question 4

Where was Negative Positive Angler filmed?

Accepted Answer

Anime and manga are not filmed the way live action is. Their backgrounds are painted from photographs of real locations, and 25 porticos is one of those real places (EP3).