How to say "incidentally" in Japanese

• ちなみにCommon
  conjunctionCovers the 'incidentally' that adds a connected aside: you supply extra information relating to the topic under discussion, in the spirit of 'in this connection' or 'in passing'.
  ちなみに、ウチのクリニックから数百すーひゃくメートルの近場ちかばに「ランプ」が建設けんせつ中ちゅうです。↗

  Incidentally a motorway ramp is being constructed in the neighbourhood, a few hundred metres away, of my clinic.
• ところでJLPT N3approx.Common
  conjunctionAlso translates 'incidentally' or 'by the way', but as a topic-changer: it introduces a remark unrelated to the current subject, in the sense of 'well' or 'now'.
  「ところでよ、そのおめーのお父とうさんはどこにいんのさ？」「横転おうてんしたトラックの下したなんよ」↗

  "By the way, where's your old man?" "Under that over-turned truck."
• ふとJLPT N3approx.Common
  adverbSeldom the connective 'incidentally' that opens a remark: ふと is an adverb describing something done or thought suddenly, casually or by accident, without premeditation, as when a recollection arises unbidden.
  彼かれはそれを見みるとふと魔まがさして盗ぬすんだ。↗

  The sight tempted him to steal.
• ついでにCommon
  adverbCovers 'incidentally' only where it means doing one thing on the occasion of another — 'while you're at it', 'at the same time' — not the connective that opens a conversational aside.
  ついでに私のも買かってきてくれますか。↗

  Can you buy one for me as well?

For 'incidentally' as a conversational aside, choose 「ちなみに」 when the remark connects to the topic and 「ところで」 when it changes the subject; 「ふと」 describes spontaneous actions or thoughts, and 「ついでに」 means 'while you're at it'.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• ちなみにby the way
• ところでby the way
• ふとsuddenly
• ついでにwhile (one is at it)
• かたがたincidentally
• それはそうとanyway
• 時にときにby the way
• ついでながらwhile I have the opportunity (I'd also like to say ...)
• それはそうとしてanyway
• ちなby the way
• その足でそのあしでstraight (from one place to another)
• でby the way