Looks like recently the Travis 37 Locale Build has started picking up pyarrow 0.11.1 https://travis-ci.org/github/pandas-dev/pandas/jobs/719430999 pyarrow 0.11.1 py37he6710b0_0 This causes the pyarrow tests to run which seem to be failing. Previously no pyarrow in env: https://travis-ci.org/github/pandas-dev/pandas/jobs/719138849 (passing build) Feels like one of our deps has started to depend to pyarrow.