To investigate the reliability and validity of 2 aquatic functionalassessment tests (Water Orientation Test of Alyn 1 and 2: WOTA1, WOTA2) for evaluating adjustment and functional ability in the aquatic environment based on the Halliwick concept. Methods: Thirty-two children with disabilities participated in the reliability study. Thirty-three other children participated in the validity study, which tested the correlations between the WOTA total score and motor performance on land. Results: Test-retest reliability for total score was found to be excellent for both WOTA1 (ICC = .97) and WOTA2 (ICC = .97). The reliability for most of the individual item scores was fair to good (kappa > .4). A positive moderately significant association was found between the WOTA total score and motor performance on land. Conclusion: Both assessments appear to be reliable and valid for assessing mental adjustment and aquatic function in children with disabilities.