The objective of this research was to investigate the influence of both unplugged and plugged coding activities on the computational thinking skills of secondary school students. Using an experimental design with a pretest-posttest control group, the study indicated that students enhanced their computational thinking skills through engagement in coding activities. Specifically, students in the experimental group, participating in unplugged coding activities (Tospaa unplugged coding activities), exhibited heightened perception and improved performance in computational thinking skills in the post-test compared to the pre-test. Conversely, the control group, involved in plugged coding activities (Scratch block-based coding), did not show a significant change in perception of computational thinking skills in the post-test compared to the pretest. However, their performance in computational thinking skills improved significantly in the post-test compared to the pre-test. Furthermore, no significant differences were observed in terms of the perception of computational thinking skills between the unplugged coding group and the plugged coding group, and similarly, no significant differences were found in terms of the computational thinking skills performance between unplugged and plugged groups. In conclusion, the study also shows a high alignment between students' perceptions of computational thinking and their actual performance in computational thinking.