If you liked the Upotte!! anime, the Anime-Planet community thinks you'd like:
In the year 2079 CE, malevolent creatures known as Worms arrived in our galaxy, wiping out mankind quickly and efficiently. Finally, when the war's outcome seemed to favor the invaders, humanity united and nuked its own planet in order to survive. Though the Worms were defeated, 50% of the Earth's land mass submerged under the ocean, and 90% of all young men were killed in battle. Now, several years later, the Worms have returned. The world's best hope for survival is the genius Karen, the swordswoman Otoha and quick-thinking Eika; together, they make up the Sonic Diver Unit, a mechanized unit capable of taking down the Worms! Yet the powers that be are skeptical of its force and aptitude. Can the girls prove their worth, and take down the enemy?
In the not-too-distant future, Earth was attacked by mysterious beings and before long over a third of the world's population was destroyed. Even after bringing to bear its full, united military strength, humanity was unable to repel the assailants and forced into using weapons of mass destruction. This was successful, but the war and its conclusion resulted in the deaths of a crushing percentage of all fighting-aged males, and Antarctica being melted, causing much of the Earth's land to sink underwater. Years later, three young girls - Otoha, a headstrong country girl; Karen, a technical genius; and the highly-disciplined and strong-willed Eika - are being trained to pilot Sonic Divers, weapons being developed lest humanity be caught off-guard once again.
Asuna Harukaze is a girl who loves tennis to the point where she practices her swings with a pitchfork while working on the family farm. At school she is a member of the Soft Tennis Club along with the enthusiastic Kotone, food-crazy Chitose and bizarre yet talented Kurusu. With a big tournament approaching, the girls are taking practice more seriously than ever, but with Asuna’s strange and perverted logic surfacing at every turn and Chitose’s inability to win a single match, can the club emerge triumphant and make it to the nationals?
Both are ecchi focused around a group of girls. Plus the characters have very similar personalities: an aggressive girl who has a bit of an ego, a perverted girl who as a thing for her teacher, and a ditzy girl with larg breasts.