Next, Vinci played at the Sydney International. Seeded ninth, she was defeated in the second round by Barbora Strýcová, 6–2, 6–3. As the 15th seed at the Australian Open, Vinci lost in the first round to world No. 35 and eventual semifinalist, CoCo Vandeweghe, 1–6, 6–7. After the Australian Open, Vinci went to compete at the St. Petersburg Trophy, where she was the sixth seed and the defending champion. She started off the tournament by beating Tímea Babos in the first round, 6–3, 3–6, 6–4 before she defeated qualifier Andrea Petkovic, 6–4, 6–4. In the quarterfinals, Vinci was defeated by eventual champion Kristina Mladenovic, 6–1, 6–4. Due to losing in the quarterfinals, Vinci failed to defend her title. At the Qatar Open, Vinci lost in the first round to qualifier Lauren Davis, 2–6, 3–6. Seeded 16th at the Dubai Tennis Championships, Vinci was upset in the first round by world No. 55, Kristýna Plíšková, 3–6, 7–5, 6–3. Vinci had a 6–3, 5–4 lead and was serving for the match before Plíšková made a comeback to win the match. Seeded 26th at Indian Wells, Vinci received a first round bye. She lost in the third round to eighth seed Svetlana Kuznetsova, 2–6, 6–2, 1–6. Seeded 25th at the Miami Open, Vinci was stunned in the second round by qualifier Taylor Townsend, 6–3, 6–2. After Miami, Vinci played at the first edition of the Ladies Open Biel Bienne. As the fourth seed, she was upset in the first round by world No. 58, Kristýna Plíšková, 6–4, 6–4. Vinci began her clay-court season at the Porsche Grand Prix. In the first round, Vinci lost to newly returned Maria Sharapova, 5–7, 3–6. Vinci had her first win since Indian Wells at the Madrid Open by defeating Daria Kasatkina in the first round, 6–1, 1–6, 6–1. In the second round, she lost to 3rd seed and eventual champion Simona Halep, 3–6, 6–2, 6–7. Vinci led 3–6, 6–2, 5–2 before Halep came back to win the match. At the Internazionali BNL d'Italia, she lost in the first round to Ekaterina Makarova, 2–6, 1–6. As the 31st seed at the French Open, Vinci was defeated in the first round by the previous year's Olympic gold medalist Monica Puig, 6–3, 3–6, 6–2. Vinci played one grass-court warm-up tournament to prepare herself for Wimbledon. As the sixth seed at the Mallorca Open, she beat lucky loser and compatriot Sara