On 1 Jun 1711 when Thomas was 24, he first married Ann Bossenger in Boston, MA.
Children of Thomas and Ann (Bossenger) Foster, born at Boston:
i. Thomas, b. 13 Jul 1713, d. after 1783, m. 1st at Boston 14 Jul 1737 Abigail Howell (dau. of Henry Howell), m. 2nd at Boston 14 Dec 1740 Sarah Banks;
ii. Mary, b. 26 Oct 1715, d. young;
iii. Edward, b. 16 Nov 1717, d. 1753, m. 1st at Boston 11 Oct 1739 Abigail Wolcot, m. 2nd at Boston 7 Mar 1744 Martha Henderson;
iv. Bossinger, b. 21 Jan 1719, d. young;
v. Ann, b. 19 Dec 1721, d. soon;
vi. Timothy, b. 1 Feb 1722/3, d. soon;
vii. Ann, b. 29 Apr 1724, m. 30 Jul 1746 Matthew Salter;
viii. Timothy, b. 8 Nov 1725, d. young;
ix. Joshua, b. 16 Feb 1727, d. young;
x. William, b. 9 May 1730, d. young;
xi. Prudence, b. 28 Jun 1731, d. young; and
xii. Elizabeth, b. 1 Oct 1732, d. ca. 1780, m. John Hurd.