Introduction: Obturation of the root canal is the most critical step in endodontic treatment, which aims to provide a hermetic seal and prevent regrowth and entry of bacteria into the canal. To achieve this, many sealers are used in endodontics. Aim: To evaluate the effectiveness of the apical seal obtained by different sealers used in conjunction with the single cone obturation technique using gutta-percha under the stereomicroscope. Materials and methods: Extracted human single-rooted teeth were taken and decoronated at the cementoenamel junction. The access cavity was prepared, and biomechanical preparation was completed. The samples were randomly assigned to four groups consisting of 20 teeth each according to the root canal sealer used and categorized as group I, group II, group III, and group IV. Group I (n = 20)—Endoseal (Prevest DenPro), group II (n = 20)—Apexit Plus (Ivoclar Vivadent), group III (n = 20)—MTA-FillApex (Angelus), and group IV (n = 20)—Ceraseal (Meta Biomed). The teeth were immersed in Indian ink for 7 days and finally transferred to methyl salicylate for diaphanization. The extent of dye penetration was measured using the stereomicroscope. Statistical data analysis was performed using analysis of variance (ANOVA) and the Tukey test. Results: Microleakage was seen in all the groups. Apical leakage was maximum for the Endoseal group, followed by MTA Fillapex, Apexit, and Ceraseal. Groups were compared by one-factor ANOVA, and the significance of the mean difference was measured using Tukey's honestly significant difference (HSD) and post hoc test. A statistically significant difference in the depth of dye penetration was observed among the groups (F = 28.66, p < 0.001). Conclusion: It was concluded that there were statistically significant differences among the experimental groups. Ceraseal endodontic root canal sealer provided a significantly better apical seal, followed by Apexit and MTA Fillapex, whereas Endoseal showed the least sealing ability.