The Palau Atmospheric Observatory (PAO) balloon-borne ozonesonde and radiosonde database V1.0 provides raw data and calculated properties of Electrochemical Concentration Cell (ECC) ozonesonde measurements in .csv format from the PAO located in Koror, Palau (7.3420° N, 134.4722° E), in the Tropical West Pacific (TWP) from 2016-2021. The ECC sondes manufactured by Science Pump Corp. (SPC), model 6A, where prepared according to standard operating procedures (SOP) (Smit et al. 2014, for more details, see references and related publications). The accompanying radiosonde are Vaisala model RS92-SGP until October 2017 and RS41-SGP afterwards.The data are calculated from raw Vaisala software output using equations and tables according to Smit et al. 2014 (script available upon request) and include e.g. ozone volume mixing ratio and partial pressure for different background current corrections, which are of relevance in the low tropospheric ozone measurement in the TWP. No additional data smoothing has been applied to the Vaisala output, but beware that the change of radiosonde models was accompanied by software changes. We advise caution with using the stratospheric data for e.g. total column ozone assessment, as there were some discrepancies between individual soundings and MLS measurements (details, see related publications). The Palau ECC record is currently being continued and will be available in the SHADOZ database in SHADOZ standard format in the near future, which will be linked here. Please email katrin.mueller@awi.de and let us know what your intended purpose for the use of the data is. You will then receive updates if an improved version becomes available.