GRAMMAR DETAIL

がてら

while one is at it

Indicates doing something else at the same time as an outing or another light activity.

Examples

散歩がてら、図書館まで本を返しに行った。

While out for a walk, I went as far as the library to return a book.

買い物がてら、駅まで歩いた。

While I was out shopping, I walked to the station.

Structure: Attach がてら to an activity noun such as 散歩 or 買い物 to describe taking the opportunity to do another errand as well.
Basic usage: 散歩がてら、図書館まで本を返しに行った。 means going to the library to return a book while also taking a walk.

Purposes of an outing versus simultaneous actions
- 散歩がてら本を返しに行く combines a walk and returning a book in one outing. ながら in 歩きながら話す focuses on walking and talking occurring simultaneously.