A blade outer air seal (BOAS) assembly includes a rotor blade configured to rotate about an axis. The BOAS assembly also includes a BOAS positioned radially outward from the rotor blade and having a forward-facing BOAS face. The BOAS assembly also includes a shroud block positioned radially outward from the BOAS, having an aft-facing shroud face, and being configured to support the BOAS. The BOAS assembly also includes a first bellows seal extending from the forward-facing BOAS face to the aft-facing shroud face and configured to reduce fluid leakage radially between the BOAS and the shroud block.