Modern combat aircraft typically feature a delta wing design with highly swept leading edges. At low to moderate angles of attack, strong longitudinal vortices develop at these leading edges. However, at high angles of attack, vortex breakdown starts to occur, causing a change in lift distribution that might induce large aerodynamic loads. To delay the onset of vortex breakdown and extend the flight envelope, current generation aircraft use mechanical slats and flaps to change the wing shape and achieve more advantageous flight characteristics. An alternative approach is the use of fluidic actuators to influence the vortical flow above the wing. While these so-called active flow control techniques have gained increased interest in recent years, most studies so far focused on low-speed applications. Therefore, the goal of the current paper is to numerically investigate the use of active flow control in the transonic flow regime. The object of this study is the DLR-F23 configuration, a generic multiple-swept delta wing configuration with leading-edge sweep angles of ϕ1 = 45°, ϕ2 = 75° and ϕ3 = 45°. In the scope of the current work, two different actuation techniques, along-the-core blowing (ACB) and spanwise blowing (SWB), are investigated numerically. The two techniques exploit different aspects of the physics of vortical flows. The goal of ACB is to inject additional momentum into the vortex core using a concentrated jet of air, thereby stabilizing the vortex and delaying vortex breakdown. In contrast, when using SWB, the goal is to strengthen a weak vortex by increasing its overall circulation. As this might lead to a destabilization of the controlled vortex, care has to be taken that the actuated vortex is still stable in the regime where the actuation is desired. Therefore, the two approaches are applied to two different vortices. On the one hand, ACB is used to stabilize the mid-board vortex that develops along the strake and that shows early vortex breakdown. On the other hand, SWB is used to strengthen the fore-body vortex, which is comparatively weak but stable up to high angles of attack. During this study, the jet strength and orientation are systematically varied for both approaches to identify optimal actuation settings. Depending on the jet settings and freestream Mach number, both approaches achieve a moderate increase in lift of between 5% to 10%.