Background: In swimming, blood lactate concentration [La*] and swimming speed are widely used for performance assessment and training prescription. The metabolic threshold (MT) can be identified through the lactate threshold (LT), as well as the glycemic threshold (GT), based on blood glucose concentration [Glic]. However, it is still unclear whether the swimming intensities corresponding to LT (vLT) and GT (vGT) speeds are similar, since results from the few studies on GT in swimmers are contradictory. Aim: To compare, verify the correlation and agreement between vLT and vGT in swimmers. Methods: 18 high-performance swimmers (15 males and 3 females) participated in the study, ERC no. 6.508.606. The athletes performed an incremental test (5 × 200 m freestyle at 80, 84, 88, 92 and 96% of individual performance) and the minimum lactate test (2 × 50 m maximum, followed by 5 × 200 m at the same intensities). [La*] and [Glic] were collected at rest, during intervals and at the end of the exercise by finger prick to determine the corresponding swimming speeds; in addition to obtaining the Rate of Perceived Exertion (RPE). Statistical analysis: vLT and vGT were compared using the paired t-test, with calculation of the effect size (Cohen's d). Agreement was assessed using Bland-Altman analysis, adopting p<0.05. Results: Threshold velocities ranged from 1.42 to 1.45 m·s*¹. No significant differences were observed between vLT and vGT in the incremental and minimum lactate tests (p>0.05; d<0.15), with excellent correlation between the methods (ICC=0.90-0.95). RPE at the thresholds showed consistent values **between 6.1 and 6.6. Conclusion: vLT and vGT showed high agreement and consistency in competitive swimmers, regardless of the protocol used, indicating similar intensities of metabolic transition. The GT proved to be a viable and less expensive alternative for identifying the MT
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