Background: Although many studies focus on short‐term side effects of radioiodine therapy, almost none studied long‐term side effects. We assessed radioiodine long‐term salivary side effects after radioiodine treatment for differentiated papillary thyroid carcinoma and compared it to short‐term morbidity within the same population.Methods: A standardized self‐administrated questionnaire was submitted in 2019 by patients treated with radioiodine between January 2011 and December 2012. These patients had already answered the same questionnaire 6 years before.Results: Our study showed a significant reduction for salivary side effects: discomfort in submandibular or parotid area, swelling, pain, a bad or salty taste in the mouth, allowing to get back to a “normal” diet.Conclusions: Our study suggests that a significant rate of patients will recover from I¹³¹ therapy salivary side effects. As almost 30% of these remissions happened during our late stage follow‐up, we highlight the necessity of a long‐term follow‐up in these patients.