Østerby church is a newer church.
The nave was built in 1867, only in 1928 was a tower built.
In 1867, Østerby chapel was built as a replacement for Hals church, which had to be closed down in 1867 due to the sand drift, which gradually depopulated the area around the church. The funds for the construction of Østerby chapel came partly from the government and partly from the residents of Læsø, here among Østerby's residents who gave 518 reigsdalers during a collection. A collection elsewhere yielded 555 rigsdaler. The state gave a subsidy of 1500 reigs. It is noteworthy that Grand Duchess Maria Feodorovna alias Queen Dagmar, daughter of Christian IX, donated 200 reigsdalers for the construction.
The baptismal font that is in the church originates from Hal's sandy church.
The pictures on each side of the altarpiece are made by a local man, Captain Hans Andreas Nielsen and the altarpiece is made by the local artist Marinus Nielsen