Purpose Vascular invasion is considered a poor prognostic feature in papillary thyroid cancer (PTC), and a relative indication for radioactive iodine treatment (RAI). Intratumoral lymphatic and vascular invasion are difficult to distinguish pathologically, and are often grouped together as “lymphovascular invasion” (LVI). However, the significance of LVI as an independent risk factor in otherwise low-risk PTC is unclear. We sought to clarify the prognostic impact of LVI in T1 PTC. Methodology A retrospective cohort study of 1327 patients treated surgically for T1 PTC between 1997 and 2024 at a tertiary referral centre was performed, using prospectively collected data. Results 265 (20.1%) patients with T1 PTC had LVI and 26 (2%) patients developed disease recurrence. RAI therapy was used in 369 (27.8%) patients, and was not independently associated with disease recurrence. Pathological factors determining the use of RAI included LVI, lymph node ratio >0.3 (LNR), lymph node macrometastases (>2mm) and tumour size. In 24 (6.5%) patients LVI was the single determinate of the use of RAI. LVI approached significance as a predictor of recurrence on univariable analysis (OR 2.26, 95% CI 0.99-5.17, p = 0.05). On multivariable analysis, independent predictors of recurrence were LNR (OR 3.99, 95% CI 1.51-10.53, p=0.01), lymph node macrometastases (OR 3.29, 95% CI 1.23-8.77, p=0.02), and tumour size (OR 1.11, 95% CI 1.02-1.21, p=0.02). In patients with LVI, the negative predictive value of LNR <0.3 and no lymph node macrometastases was 100%. Conclusion The presence of LVI is not independently prognostic for disease recurrence in T1 PTC and, in the absence of other high-risk features, should not be considered an indication for RAI.