Catechins in tea crop are correlated with quality and valued for healthy benefits. The components vary with conditions such as cultivar, season, elevation and soils. A study underscored the effect of genotype environment interaction on tea quality. Complete Randomized Block Design in 3-replicates was adopted during wet and dry seasons in 2016at 3-locations. Genotypes were analyzed for quality using ISO 14502-2:2005 procedure. ANOVA showed significant (p = 0.05) variation among catechins. Genotypes responded differently for locations and seasons on quality variables. EGCG was the most abundant catechin. TRIT 201/16, TRIT 201/43 and TRFK 303/577 had significantly similar and higher % TC but non-significantly different % EGCG. TRIT 201/43 excelled on %EGC, %CAFF, %ECG and %TC, while TRIT 201/16 for %GA. Main location effects influenced higher %EGC, %ECG, %EGCG and %TC at Ilenge. Significantly higher %EGC, %ECG, %EGCG and %TC were evident during wet season. Genotype location exhibited highest %EGCG and %TC for TRIT 201/43 at Ilenge, while TRIT 201/16 for %CAFF and %ECG at Marikitanda. Genotype × season had highest effect on %EGCG and %TC for TRIT 201/16 during wet season. TRFK 6/8-dry season excelled on %EGC; SFS150-dry season on %C; TRIT 201/16-dry season on %ECG and TRIT 201/43-wet season on %CAFF. Location season had highest %EGCG and % TC at Ilenge during wet season. %GA was highest at Ngwazi-during both seasons, and only during wet season at Marikitanda. TRIT 201/16 had all desirable stability parameters for %GA at Ngwazi, while SFS150 for %EGC at Ilenge. TRIT 201/16 and TRIT 201/43 had higher %CAFF and %ECG at Marikitanda. TRIT 201/43 excelled on %EGCG and %TC at Ilenge. Significant positive correlations were for %EGC with %ECG and %catechin; %caffeine with %EGCG and %TC; %EGCG with %TC. TRFK 6/8 and TRFK 303/577 met stability requirements for %GA; TRIT 201/16 for %Caffeine, while TRFK 303/577 and SFS150 for %EGC and %ECG and TRIT 201/43 for %TC.