The church is built of limestone and comprises a nave with a straight-ended chancel, a west tower and an eastern sacristy, entered through the base of the tower and via a doorway in the middle of the south wall. The western half of the present nave dates from a Romanesque church of the early 13th century, which likely had a narrower apse-ended chancel, traces of which survive in rounded base stones. The tower itself was added later in the same century.
Around 1300 an ambitious rebuilding began but was never completed. A taller new chancel, as wide as the nave, replaced the earlier one. Then, between 1838 and 1840, the triumphal arch wall and the chancel vault were demolished, joining nave and chancel into a single unified space beneath one roof. The Gothic chancel doorway was shifted slightly westward, large symmetrical windows were inserted, and a new sacristy was built to the east, replacing an older one on the chancel's north side that was removed.
This 19th-century campaign is why Eksta stands out among Gotland's churches: few others were so thoroughly altered after the Middle Ages. The tower retains a form typical of the island, rising to a tall spire set on masonry gables at each compass point, pierced by intact round-arched, colonnetted sound openings arranged in two tiers.
Four medieval doorways survive. Those on the original nave's south and north sides, whose outer surrounds were uncovered in 1947, are Romanesque, as is the tower doorway; the north doorway is thought to have been moved here from the earliest chancel when that was rebuilt in the 14th century. The doorway at the centre of the south front is Gothic, with an elaborately moulded, multi-stepped surround.
Inside, a simple wooden barrel vault covers the nave, and plain walls reveal occasional exposed medieval wall paintings from the 15th century. The pulpit and altarpiece, both dated to 1675, were acquired in the 19th century; sources differ on the exact year and on their origin, with one account linking them to Össeby church, said to have been damaged by storm. A stained-glass pane in the round east window, possibly acquired at the same time, is thought to date from the later 13th century.