A liquid crystal polyester fiber includes a liquid crystal polyester having a tensile strength is 25 cN/dtex to 30 cN/dtex, and an orientation degree of the fiber is 94% to less than 100%. The liquid crystal polyester has repeating units of Formula (1), Formula (2), and Formula (3). At least one repeating unit of Formula (1), Formula (2), and Formula (3) contains 2,6-naphthylene. A content of the repeating unit containing the 2,6-naphthylene is 68 to 80 mol % with respect to a total content of all the repeating units. The liquid crystal polyester fiber has a fiber diameter of 5 to 100 μm; (1) —O—Ar1—CO—, (2) —CO—Ar2—CO—, and (3) —X—Ar3—Y—, wherein Ar1 represents phenylene, naphthylene, or biphenylylene, Ar2 and Ar3 each independently represent phenylene, naphthylene, or biphenylylene, Ar1, Ar2, or Ar3 contains 2,6-naphthylene, X and Y independently represent oxygen or —NH—, and Ar1, Ar2, or Ar3 may be substituted.