An image decoding method obtains pieces of coded data which are included in a bitstream and generated by coding tiles obtained by dividing a picture. The pieces of coded data are decoded to generate image data of the tiles. When obtaining the pieces of coded data, tile boundary independence information is further obtained from the bitstream. The tile boundary independence information indicates whether each boundary between the tiles is a first or second boundary. Image data of a first tile is generated by decoding a first code string included in first coded data with reference to decoding information of an already-decoded tile when the tile boundary independence information indicates the first boundary. The first code string is decoded without referring to the decoding information of the already-decoded tile when the tile boundary independence information indicates the second boundary.