Technical Abstract: Personal-size watermelon [Citrullus lanatus (Thunb.)], cultivars Valdoria and Vanessa were evaluated at 20, 30, 40 or 50 days after anthesis to determine a means of determining maturity at harvest. Fruit circumference, weight, ground-spot color, and number of senescent tendrils were measured for each watermelon. Soluble solids content (SSC), pH and SSC: total acid ratio (SS:TA) of each watermelon were determined to provide an indication of internal maturity. Regression and AIC fit statistics analyses were performed to determine significant relationships and best predictors for external indicators of internal maturity factors. External predictors were most closely linked to fruit pH, rather than SSC or SSC/TA. Of the external indicators tested, fruit weight, circumference, number of senescent tendrils, and CIE b* values were best related to fruit pH. According to the regression models, two completely senesced tendrils, a circumference of 53 cm, weight of 3 kg and CIE b* coordinate groundspot value of 40 are each sufficient to predict maturity when pH is used as the internal indicator of maturity.