Background and Objectives: Décolleté photodamage is a common condition typically treated with light and energy-based devices. This study investigated the efficacy and safety of a fractional 1,927 nm thulium laser (TL) alone and combined with photodynamic therapy (PDT). Study Design/Materials and Methods: In a 12-week follow-up study, participant décolletés were divided into four treatment areas and randomized to receive a single treatment with field-directed TL, PDT, combination TL-PDT, or lesion-directed curettage control. All actinic keratoses (AKs) underwent lesion-directed curettage before randomization. TL was delivered at 20 mJ/mb, 500 mJ/cm² fluence, 5 W, and 8 (n = 6 pts.) or 16 (n = 6 pts.) passes. PDT was performed with 16% methyl aminolevulinate (MAL) creme incubated for 3 h, followed by red light-emitting diode light at 37 J/cm². Outcome measures included clinical assessment of overall photodamage and specific subcomponents, assisted by optical coherence tomography (OCT) imaging. Results: Twelve women with moderate to severe photodamage on the décolleté and a cumulative total of 184 thin grade I AKs were included. Field-directed treatments TL and combination TL-PDT equally improved the overall photodamage, mottled pigmentation, and rhytides compared with lesion-directed control (P < 0.05). The skin texture improved by TL alone and was further improved by combining TL and PDT (P < 0.05). Median AK complete responses were similar for field-directed interventions TL-PDT (100%), TL (90%), PDT (82%), and lesion-directed curettage control (52%) (P = 0.464). Patients presented with mild local skin responses, slightly more pronounced when combining TL with PDT versus individual treatments (P < 0.05). No scarring or adverse events were observed. Conclusions: The 1,927 nm fractional thulium laser is an effective, tolerable, and safe field-directed treatment for décolleté photodamage. Provided alone, TL proved to be as effective as combined TL-PDT for overall photodamage, while a greater improvement in skin texture was achieved using TL and PDT in combination. Lasers Surg. Med.