As a contribution to the second REgional Carbon Cycle Assessment and Processes effort, we compare net and anthropogenic sea‐air CO2 fluxes, CO2 accumulation rates in the ocean interior and their trends in the Pacific Ocean by analyzing results from state‐of‐the‐art observation‐based estimates and global ocean biogeochemistry models (GOBMs) over the period 1985–2018. The ensemble‐mean net CO2 fluxes integrated over the Pacific (44°S–62°N) are −0.41 ± 0.12 PgC yr−1 from pCO2 products and −0.51 ± 0.16 PgC yr−1 from GOBMs. The anthropogenic CO2 flux from GOBMs (−0.71 ± 0.10 PgC yr−1) is 1.4 times as large as the net CO2 flux, with particularly large anthropogenic uptake in the equatorial region (−0.34 ± 0.03 PgC yr−1) significantly offsetting the large natural CO2 outgassing there (+0.72 ± 0.06 PgC yr−1). The basin‐wide net CO2 uptake has increased at similar mean rates of −0.09 ± 0.06 and −0.08 ± 0.02 PgC yr−1 decade−1 in pCO2 products and GOBMs, respectively, comparable with the increase in anthropogenic CO2 uptake of −0.10 ± 0.01 PgC yr−1 decade−1 in GOBMs. However, a notable mismatch in the trend of the net CO2 flux change that exists between pCO2 products (+0.00 ± 0.02 PgC yr−1 decade−1) and GOBMs (−0.04 ± 0.01 PgC yr−1 decade−1) in the equatorial region is yet to be resolved. The rate of anthropogenic CO2 accumulation from GOBMs is +0.76 ± 0.17 PgC yr−1. This is nearly balanced with the anthropogenic CO2 flux and is also encompassed by the previous observation‐based estimates.