Discrete water sample data of carbonate system parameters (pHt, Total Alkalinity, Dissolved Inorganic Carbon), salinity, temperature, depth, and Rhodamine WT fluorescence were collected during the Ocean Alkalinity Enhancement field trials in Bedford Basin/Halifax Harbour for the period of August to October 2023. The samples were collected in the vicinity of Nova Scotia Power's Tufts Cove Generating Station outfall, which was used by Planetary Technologies to deliver alkalinity (magnesium hydroxide, Mg(OH)2) into the harbour, at a depth of approximately 1-2 m. The field trials involved the release of 14.4 kg of Rhodamine WT on August 10 from 14:00 to 3:45 UTC, 10.8 kg of Rhodamine WT and 2270 kg of alkapHix material on September 12 from 13:39 to 19:10 UTC, and 10.8 kg of Rhodamine WT and 2400 kg of brucite on October 3 from 12:30 to 18:30 UTC. All sampling was conducted onboard the Eastcom dive boat using a Niskin bottle lowered into the water from the side of the vessel. The Mg(OH)2 content of the alkapHix is 96-99% and the Mg(OH)2 content of the brucite is 79%.