A drink bladder, comprising a hollow body for receiving a liquid, wherein - the hollow body has at least one flexible wall (100, 101) and at least one port for connection to a drinking tube, - the liquid can be filled into the hollow body via an opening that is formed between a first closing portion and a second closing portion and can be closed by a closure device of the drink bladder, and - the closure device includes a first closure part on the first closing portion and a second closure part on the second closing portion, wherein - the first closure part has a first strip body longitudinally extended along a transverse direction (x), - the second closure part has a second strip body longitudinally extended along the transverse direction (x), characterized in that - the first closure part and the second closure part cooperate in a magnetically attracting manner in such a way that in a closed position of the closure device the first closing portion and the second closing portion rest against each other and form a closure compound with the first and second closure parts (21, 20), - the closure compound can be adjusted from a release position, in which the first and second closing portions (104, 105) can be properly separated from each other against a magnetic force applied by the first and second closure parts (21, 20) to clear the opening, by folding or rolling the first and second closing portions (104, 105) at least once into a sealing position, - the closure device comprises a securing mechanism via which the closure compound disposed in its sealing position is secured and - the securing mechanism includes at least one securing part (3.1, 4.1; 3.2, 4.2; 223A, 204A; 223B, 204B; 216, 226; 207) which secures the closure compound in the sealing position via a form fit. - the hollow body has at least one flexible wall (100, 101) and at least one port for connection to a drinking tube, - the liquid can be filled into the hollow body via an opening that is formed between a first closing portion and a second closing portion and can be closed by a closure device of the drink bladder, and - the closure device includes a first closure part on the first closing portion and a second closure part on the second closing portion, wherein - the first closure part has a first strip body longitudinally extended along a transverse direction (x), - the second closure part has a second strip body longitudinally extended along the transverse direction (x), characterized in that - the first closure part and the second closure part cooperate in a magnetically attracting manner in such a way that in a closed position of the closure device the first closing portion and the second closing portion rest against each other and form a closure compound with the first and second closure parts (21, 20), - the closure compound can be adjusted from a release position, in which the first and second closing portions (104, 105) can be properly separated from each other against a magnetic force applied by the first and second closure parts (21, 20) to clear the opening, by folding or rolling the first and second closing portions (104, 105) at least once into a sealing position, - the closure device comprises a securing mechanism via which the closure compound disposed in its sealing position is secured and - the securing mechanism includes at least one securing part (3.1, 4.1; 3.2, 4.2; 223A, 204A; 223B, 204B; 216, 226; 207) which secures the closure compound in the sealing position via a form fit. - the first closure part has a first strip body longitudinally extended along a transverse direction (x), - the second closure part has a second strip body longitudinally extended along the transverse direction (x), characterized in that - the first closure part and the second closure part cooperate in a magnetically attracting manner in such a way that in a closed position of the closure device the first closing portion and the second closing portion rest against each other and form a closure compound with the first and second closure parts (21, 20), - the closure compound can be adjusted from a release position, in which the first and second closing portions (104, 105) can be properly separated from each other against a magnetic force applied by the first and second closure parts (21, 20) to clear the opening, by folding or rolling the first and second closing portions (104, 105) at least once into a sealing position, - the closure device comprises a securing mechanism via which the closure compound disposed in its sealing position is secured and - the securing mechanism includes at least one securing part (3.1, 4.1; 3.2, 4.2; 223A, 204A; 223B, 204B; 216, 226; 207) which secures the closure compound in the sealing position via a form fit.