Combine the tangerine juice, lemon juice, oil, honey, coriander, thyme and garlic in a large plastic storage container. Whisk to combine. Add the sea bass fillets and turn to coat in the marinade. Cover with a lid and marinate in the refrigerator, flipping once halfway through, 30 minutes.
Preheat an outdoor grill or large cast-iron grill pan to medium heat. While the grill heats up, remove the fish from the marinade and pat fairly dry with paper towels. (There should be a light coating of marinade on the fish but not too much, because excess oil will cause flare-ups on the grill.) Discard the marinade. Season the fish liberally on all sides with salt and pepper.
Place the fish skin-side down on the hot grill. Cook until the skin is light golden brown and crispy, 3 to 5 minutes. Carefully flip the fish and cook until just cooked through and the center is opaque, 3 to 5 minutes more.
While the fish is cooking, add the tangerines to the grill cut-side down. Grill until the flesh is deeply charred in spots, about 10 minutes. Remove from the grill and cool slightly.
To serve, transfer the grilled fish to a large platter. Nestle the grilled tangerines around the fish and top with the sprigs of mint. Serve immediately.