1A shipping method that sends mail or parcels by boat rather than by air; cheaper but slower than airmail.
重い荷物なので船便で送ることにした。
Since the package was heavy, I decided to send it by sea mail.
船便だと届くまでに1ヶ月ほどかかる。
By sea mail, it takes about a month to arrive.
引っ越しの荷物を船便で海外に送った。
I shipped my moving boxes overseas by sea freight.
2Regular ferry or steamer transport along a fixed route, often connecting to islands.
台風のため、離島への船便が全て欠航した。
Because of the typhoon, all ferry services to the outlying island were canceled.
この島へは一日に二便しか船便がない。
There are only two ferry sailings a day to this island.