〜がてら

Indicates doing a second thing while performing one main action, typically going somewhere: one trip serves two purposes. It attaches to movement- or outing-related nouns and verbs (散歩, 買い物, 見物, 出かける). The style is slightly literary and adult; in casual conversation 〜ついでに is more common, and unlike ながら it does not mean two actions performed simultaneously moment by moment.

• 散歩がてら、パンを買ってきた。

  さんぽがてら、パンをかってきた。

  I bought some bread while out for a walk.

• 買い物がてら、駅前の figures…

  かいものがてら、えきまえのほんやによった。

  On my shopping trip, I dropped by the bookstore in front of the station.

• 京都へ出張しがてら、古いお寺を見て回るつもりだ。

  きょうとへしゅっちょうしがてら、ふるいおてらをみてまわるつもりだ。

  While on a business trip to Kyoto, I plan to visit some old temples.