Self-compacting geopolymer concrete (SCGC) is a geopolymer concrete (GPC) possessing the ability to self-consolidate. Aluminosilicate minerals and alkaline activator solution (AAS) are the two principal components that are majorly accountable for the geo-polymerization process. Among the precursors available, ground granulated blast furnace slag (GGBFS)-based SCGC mixes exhibit better performance towards both short-term and long-term characteristics. The current study describes the impact of various alkaline activators like sodium hydroxide (SH), potassium hydroxide (PH), sodium silicate (SS), and potassium silicate (PS) in varying proportions on the fresh properties of GGBFS-based SCGC mixes. Nine mix designs were prepared including a control mix with SH and SS as alkaline activators. Four mixes formed with a combination of SS along with hydroxide solutions of sodium and potassium at changing proportions (SH: PH) [(75:25), (50:50), (25:75), (0:100)]. Similarly, another four mixes were proposed with constant SH solution in addition to silicate solutions of sodium and potassium at different combinations (SS: PS) [(75:25), (50:50), (25:75), (0:100)]. Mix proportions were prepared as per laboratory material characterization results based on Indian standards (IS) of binder materials (GGBFS), natural coarse aggregates (NCA), and natural fine aggregates (NFA) along with suppliers-provided properties of alkaline activators and superplasticizers (SP). The workability results are explained through the filling ability (FLA) (slump flow, T50cm slump, V-funnel experiments); passing ability (PA) (L-box, J-ring experiments), and segregation resistance (SR) (V-funnel at T5minutes experiment) capability. The result signifies that SCGC mixes should not be prepared with 100% SH and SS or 100% PH and SS as AAS. SCGC mix with SH and SS: PS (25:75) exhibits the best workability results towards fresh properties of SCGC.