You can apply, your own style to native base tabs like below.
<Tabs tabBarUnderlineStyle={{borderBottomWidth:2}}>
<Tab heading="Popular" tabStyle={{backgroundColor: 'red'}} textStyle={{color: '#fff'}} activeTabStyle={{backgroundColor: 'red'}} activeTextStyle={{color: '#fff', fontWeight: 'normal'}}>
// tab content
</Tab>
<Tab heading="Popular" tabStyle={{backgroundColor: 'red'}} textStyle={{color: '#fff'}} activeTabStyle={{backgroundColor: 'red'}} activeTextStyle={{color: '#fff', fontWeight: 'normal'}}>
// tab content
</Tab>
</Tabs>