In this paper, we construct several new families of quantum codes with good parameters. These new quantum codes are derived from (classical) t-point ($$t\ge 1$$t?1) algebraic geometry (AG) codes by applying the Calderbank---Shor---Steane (CSS) construction. More precisely, we construct two classical AG codes $$C_1$$C1 and $$C_2$$C2 such that $$C_1\subset C_2$$C1?C2, applying after the well-known CSS construction to $$C_1$$C1 and $$C_2$$C2. Many of these new codes have large minimum distances when compared with their code lengths as well as they also have small Singleton defects. As an example, we construct a family $${[[46, 2(t_2 - t_1), d]]}_{25}$$[[46,2(t2-t1),d]]25 of quantum codes, where $$t_1 , t_2$$t1,t2 are positive integers such that $$1