Spatial Cognition plays a very significant role towards the success of various scientific disciplines, as literature has demonstrated clearly that these skills are highly demanded for learning and pursuing STEM fields. This study was carried out to explore the level of spatial cognition among high school students and examine the learners' readiness towards STEM subjects. The study was descriptive and a quantitative research method was applied. A standardized tool was utilized to assess the spatial cognition of the students of the science group of grades 9 to 12th. 130 students from 13 to 18 years with an average age of 15.5 were administered the Mental Rotation Test (MRT) for measuring spatial cognition and readiness was measured through statements using a 5-point Likert scale. The results were analyzed using the SPSS-21 version. It was found that the majority of the students had low level of spatial cognition, which hindered their readiness regarding STEM in post-pandemic situations. There was a positive linear relationship between spatial cognition and readiness of the learners’ regarding STEM subjects. Moreover, it was concluded that there was a significant impact of spatial cognition on the readiness of the learners towards STEM. Therefore, it was recommended that the science curriculum should be designed in such a way that incorporates spatial reasoning skills among students. This study's findings serve as a baseline to attract the science educationists towards a challenging predictor.