Eleven new secondary metabolites [kuroshines H-J (<b>1</b>-<b>3</b>), 27-methyl glycinate zoanthenamine (<b>4</b>), 27-hydroxyzoanthenamine (<b>5</b>), 27-methyl glycinate kuroshine A (<b>6</b>), 27-hydroxykuroshine A (<b>7</b>), 3β-hydroxy-28-deoxyzoanthenamine (<b>8</b>), 14α-hydroxy-28-deoxyzoanthenamine (<b>9</b>), 27-hydroxy-28-deoxyzoanthenamine (<b>10</b>), and kuroshine K (<b>11</b>)], along with seven known compounds (<b>12</b>-<b>18</b>), were isolated from the zoantharian <i>Zoanthus vietnamensis</i>. The structures of all isolated components were elucidated by spectroscopic data (IR, MS, NMR, and UV), especially 2D NMR analyses. The relative configurations of <b>1</b> and <b>2</b> were confirmed by using single-crystal X-ray crystallography. Compounds <b>1</b>-<b>3</b> were found to have an unprecedented ether linkage between C-15 and C-28, while the unusual substituent methyl glycinate, attached at C-27 in compounds <b>4</b> and <b>6</b>, was found for the first time in zoanthamine-type alkaloids. The anti-lymphangiogenic activities of 17 isolated compounds were evaluated. Compounds <b>4</b>, <b>5</b>, and <b>10</b> exerted promising anti-lymphangiogenic functions by reducing cell growth and tube formation of human lymphatic endothelial cells (LECs). In addition, the structure-activity relationships of the isolated alkaloids against lymphangiogenesis of LECs are discussed.