Bamboo can be used in a variety of ways, including as fuel and as household and construction materials. Due to its versatility, the material is of high economic value. This study investigated the fuel properties of six bamboo species grown in Indonesia. Each bamboo sample was carbonized at different temperatures. Proximate and ultimate analyses were carried out on the bamboo samples. The thermal maturity of the bamboo samples as a solid fuel was investigated by the van Krevelen diagram. The efficiency of bamboo at each carbonizing temperature was determined based on the char yield, energy densification rate, energy efficiency, and calorific value. The results showed that the ash and fixed carbon contents of carbonized bamboo increased with an increasing carbonization temperature; while the volatile matter decreased. Significant changes in the fuel properties were observed between 200 °C and 400 °C. Carbonized bamboos showed lower sulfur contents in comparison to other fossil fuels. Ampel bamboo showed a calorific value of 18 MJ/kg to 32 MJ/kg, which was the highest value among the samples. Bamboo carbonized at temperatures above 600 °C showed a thermal maturity of coal grade. The results of this study can be used for utilizing Indonesian bamboo as a fuel source.