The increase in white wine sales and the scarcity of studies on their bioactive potential compared to red wines motivated this study, which aimed to evaluate the total phenolic compounds (TPCs) and total antioxidant capacity (TAC) in five Chardonnay white wines, both before and after in vitro gastrointestinal digestion, as well as to analyze the bioaccessibility (BA%) of TPCs. Phenolic compounds were determined using HPLC; TPCs (mg GAE/L) were quantified by the Folin–Ciocalteu method; and TAC (µM Trolox equivalent) was measured through the reduction of Cu²⁺ to Cu⁺. The in vitro digestion process included a gastric phase with pepsin (pH 1.3, 37°C, 1 hour), followed by an intestinal phase with pancreatin (pH 6.7, 37°C, 2 hours). The TPC concentrations varied as follows: Wine 1, from 290.9 ± 0.63 mg GAE/L to 119.4 ± 11.32 mg GAE/L (BA% 41.04%), with TAC decreasing from 2720 ± 47.02 µM to 1343.3 ± 55.89 µM; Wine 2, from 156.0 ± 11.68 mg GAE/L to 109.5 ± 6.85 mg GAE/L (BA% 70.19%), with TAC decreasing from 1753.8 ± 58.90 µM to 730.55 ± 228.72 µM; Wine 3, from 296.9 ± 14.03 mg GAE/L to 214.2 ± 37.45 mg GAE/L (BA% 72.14%), with TAC decreasing from 2586.66 ± 56.59 µM to 1229.44 ± 121.03 µM; Wine 4, from 184.5 ± 31.35 mg GAE/L to 144.5 ± 19.42 mg GAE/L (BA% 78.31%), with TAC decreasing from 2560 ± 23.51 µM to 958.55 ± 37.44 µM; and Wine 5, from 344.6 ± 43.69 mg GAE/L to 217.6 ± 18.09 mg GAE/L (BA% 63.14%), with TAC decreasing from 2985.55 ± 59.16 µM to 1647.22 ± 158.34 µM. The most prominent phenolic compounds identified were epicatechin and quercetin-3-rhamnoside. In summary, TAC decreased after digestion but remained at significant levels, as did BA%, suggesting that white wines may contribute to the intake of bioactive compounds with antioxidant potential. These findings emphasize the need for further investigation into the interaction between bioactive compounds from natural sources, such as white wine, and their role in modulating antioxidant enzyme systems, taking into account the biochemical transformations of phenolic compounds during gastrointestinal digestion and their effects on the human body.