How far in advance should I book flight tickets from Rio de Janeiro to Buenos Aires?

The best time to book your flight from Rio de Janeiro to Buenos Aires is <b>21 days before departure</b>. See how prices for flights change on the Rio de Janeiro to Buenos Aires route.预订里约热内卢至布宜诺斯艾利斯的航班，最佳时机为出发前 <b>21天</b>。请查看里约热内卢至布宜诺斯艾利斯航线机票价格的变动情况。