While not closely related taxonomically, salps and siphonophores share a “multi-jet” swimming strategy in which thrust for the colony is produced by multiple zooids, each of which produces its own jet. Jets can be reoriented for thrust vectoring and fired either asynchronously or synchronously, providing a range of possible propulsion strategies. We developed a numerical model of multi-jet swimming to test the relative advantages of multi-jet propulsion strategies while keeping other factors, such as thrust, constant. We used model runs parameterized based on high-speed videography of free-swimming siphonophores (Namomia bijuga) to compare asynchronous and synchronous swimming modes. Asynchronous swimming–in which nectophores (swimming zooids) jet sequentially–is a steady swimming mode, while synchronous swimming–in which nectophores jet simultaneously–is commonly used for escape swimming. For the same thrust input, synchronous swimming yields a lower propulsion efficiency, higher cost of transport, and lower mean swimming speed than asynchronous swimming. However, maximum swimming speed is higher for synchronous than for asyncronous swimming. We also tested the consequences of varying nectophore numbers. As the number of nectophores increases, asynchronous swimming produces thrust over a larger fraction of the swimming cycle, and the magnitudes of the aforementioned differences between swimming modes increase. These results demonstrate how multi-jet swimmers can vary the timing of thrust production to favor energy conservation for steady swimming or maximum swimming speed for escape swimming.