The natural variability of seawater pH (pH_sw) is important for predicting how pH will change as a result of ocean acidification, but it is not well constrained due to the limited instrumental records. Coral boron isotopes (δ¹¹B) offer an alternative method for tracking pH_sw variability over time, extending the record back centuries. Here, we present a compilation of new and previously published century-long coral δ¹¹B records from global coral reefs to study pH_sw variability from an integrated perspective. We show that all global coral δ¹¹B records exhibit similar fluctuation cycles associated with the Atlantic Multidecadal Oscillation (AMO), implying that the Atlantic climate has a dominant control over coral δ¹¹B multidecadal variability. We interpret this linkage as a manifestation of the control of AMO-driven wind speed changes on seawater pH via either gas exchange or metabolic effect, rather than a not-yet-determined influence of other external factors (e.g., light, nutrient, circulation) on coral internal calcifying fluid pH upregulation in addition to temperature. This finding not only suggests that wind speeds play an important role in regulating the multidecadal ocean carbon cycle, but it also suggests that AMO may play a role in the variability of (sub)tropical wind speeds.