Recent developments in shallow water Ocean Acoustic Tomography (OAT) propose the use of an original configuration composed of two source-receive vertical arrays and wideband sources. The recording space has thus 3 dimensions (3D) with two spatial dimensions and the frequency dimension. Using this recording space, it is possible to build a 3D estimation space which gives access to the three observables linked to the acoustic arrivals: the Direction Of Departure (DOD), the Direction Of Arrival (DOA) and the Time Of Arrival (TOA). The main interest of this 3D estimation space is its capability to separate acoustic arrivals which usually interfere in the recording space due to multipath propagation. A 3D estimator called Double- Beamforming (D-BF) has already been developed but remains limited in resolution. In this paper, new 3D high-resolution estimators Double-Capon (D-Capon) and Double-MUSICAL (DMUSICAL) are proposed to achieve this task. The OAT configuration allows a single recording realization to estimate the cross-spectral data matrix. 3D smoothing techniques are thus proposed to increase the rank of the matrix. The estimators are validated on data recorded in an ultrasonic tank and their detection performances are compared to existing 2D and 3D methods.