東岸沿いに
Adverb
1
adverb (fukushi)
along the east coast;along the eastern seashore
沿い
Common
suffix
1
suffix
along (a river, coast, railway, etc.);on (e.g. a street)
after a noun; usu. 〜に
船は海岸沿いに航行していた。
The ship sailed along the coast.
Other forms
添い 【ぞい】 (rarely used kanji form)