A low-cost and additively manufactured 3D Antenna-in-Package (AiP) with quasi-isotropic radiation is proposed for a marine animals monitoring system. The antenna is based on a meandered dipole folded as a split ring resonator (SRR) structure, which can generate simultaneously a pair of orthogonal electric and magnetic dipoles, thus providing a quasi-isotropic radiation pattern. The antenna (integrated with a balun) has been inkjet-printed on a 3D-printed buoyant cone structure, which acts also as the system package to house the electronics and the battery. The antenna designed at 2.4 GHz is electrically small, with a ka = 0.49, and has a bandwidth of 70 MHz (2.9%). The measured gain deviation of the antenna (maximum to minimum) is near 3 dB in bandwidth, thus qualifying it as a quasi-isotropic antenna. Field tests of the antenna in the active state (integrated with the electronics) confirm a reliable communication range of 240 m in any direction in the azimuthal plane.