Surgical sutures must retain sufficient load-bearing capacity during healing, yet aqueous exposure can alter the performance of different polymers and filament architectures. This exploratory in vitro comparison evaluated nine USP 4-0 suture materials immersed in Fusayama artificial saliva or phosphate-buffered saline (PBS) at 37 °C. For each post-immersion material–medium–time condition, three replicate specimens were evaluated (n = 3); the dry Day 0 reference comprised three evaluable traces for seven materials and two for PP and SI. The media were not renewed during the assigned exposure interval. The primary endpoint was maximum breaking force (Fmax) of the suture–knot assembly; apparent wet-state mass change, medium pH, macroscopic integrity, and force–crosshead displacement behavior were complementary descriptors. PGLA retained 24.4% of the dry baseline Fmax in Fusayama solution and 37.1% in PBS at Day 14. PGA retained 26.2% in Fusayama at Day 21 and 20.3% in PBS at Day 28, while PD retained 25.2% and 18.1% at Day 21. Among non-absorbable sutures at Day 28, silk and nylon showed the lowest retention (28.4–41.6%), whereas NL, PB, PP, and SB showed more persistent but medium-dependent and sometimes non-monotonic responses. Large positive wet-state mass changes did not consistently parallel loss of Fmax. All six non-absorbable materials had higher Day-28 Fmax in PBS than in Fusayama solution. Owing to the modest replication, dry-versus-wet baseline mismatch, and repeated material trajectories, the inferential analyses are treated as exploratory rather than confirmatory.