Slow earthquakes are generally distributed in regions surrounding seismogenic zones along the plate boundaries of subduction zones. In the Costa Rica subduction zone, large regular interplate earthquakes with a magnitude of 7–8 occur repeatedly, and a tsunami earthquake occurred in the northern part in 1992. To clarify the spatial distribution of various slip behaviors at the plate boundary in the Costa Rica subduction zone, we detected and located very low frequency earthquakes (VLFEs) using a grid-search matched-filter technique with synthetic templates based on a regional three-dimensional model. VLFEs were activated in September 2004 and August 2005, and most of the VLFEs were located near the trench axis at a depth range of 5–10 km, the updip of the seismogenic zone. The spatial distribution of VLFEs complements the slip areas of large earthquakes and the tsunami earthquake. Low frequency tremor signals were also found in high-frequency seismogram envelopes within the same time windows of detected VLFEs; thus, we also investigated the energy rates of tremors accompanied by VLFEs. The range of scaled energy, which is the ratio of the seismic energy rate of a tremor to the seismic moment rate of accompanying VLFE, was 10^-9–10^-8. This value is similar to that in shallow slow earthquakes in the Nankai subduction zone. The similarity of characteristics and distribution of shallow slow earthquakes in the Costa Rica and Nankai subduction zones may be due to common tectonic features, such as age, temperature, or the presence of accretionary prisms.