遅刻をする

You combine the noun chikoku (lateness) with the verb suru (to do). In casual speech, you can drop the o and just say chikoku suru. If you want to sound more polite, use chikoku o shimasu. To apologize for being late in the past, use chikoku o shimashita. It’s simple, direct, and very common in daily life.

Use this when you are late for a fixed schedule. This includes morning classes or your office start time. It's perfect for texting a friend when you're stuck in traffic. You can also use it when explaining why you missed the first half of a movie. Basically, if there was a clock involved, this phrase fits.

Don't use this for general delays that aren't about an appointment. For example, if a train is late, you don't say the train is doing chikoku. Instead, you use okureru. Also, don't use it for 'being late' in a life-stage sense. You wouldn't use it to say you started a career late. It is strictly for the clock and the calendar.

In Japan, being 'on time' actually means being five minutes early. Arriving exactly at the start time can sometimes be seen as a chikoku! Punctuality is a sign of respect for others' time. If you do chikoku, a sincere apology is always expected. Even a one-minute delay is often reported in Japanese offices. It might feel intense, but it keeps the society running like a Swiss watch.

You might hear chikoku-ma, which means a 'lateness demon' or chronic late-comer. Another variation is chikoku-todoke, which is an official 'lateness report' for school. If you are just a little late, you might say sukoshi chikoku suru. If you are significantly late, you might use oohaba ni chikoku suru. Always pair it with a bow if you're in person!